Table of contents

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1. Intro
2. Reference - Wiring Simplified
3. Guide Overview
1. Electrical Modules for the Seed Eco-Home 2
4. Wire, Cost, and Ampacity
• Breakers and Ampacity
5. Common Sense Considerations
6. Numeracy and Calculations
7. Zero Energy House
8. Codes
9. NEC for Dummies
• Boxes + Fill Calculations + Conduit Fill
• Boxes and High Amp Boxes
• Box Selection
• Electrical Diagram
• Outlets and Lights
• Kitchen + Heat Pump
• Hallways, Closets, Bathrooms, Attic, Garage
10. Load Calculations
11. Electrical Diagram for Build Plans
12. Heights, locations of lights, outlets, switches
13. Required Circuits + Devices

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• Costs
• Power Meter and Panel
• Wireless switches
• Bathroom Electrical
• Superefficiency
• Bullshit Alert
• Equipment Space Requirements
• Definitions
• Service Entrance Considerations
• Solar Power
• Bonding
• Solar Hydrogen
• Specifics:
• Range Hoods
• MWBC and single pole breakers - Common shutoff not required, but common maintenance shutoff is required
• 14/2/2 vs 14/3 - 2 single pole AFCI instead of 2-pole AFCI (expensive) can be used with 14/2/2
• MWBC + AFCI requires 2-pole AFCI to work properly. Further, handle tie is not for trip protection - it is for worker protection when circuit is flipped manually. See exranger06
• Screw and Clamp connectors - this is the desired and easy route, is it more solid than

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Grounding System Logic from Power Company to House

1. 3 wires come from the pole transformer to ground - 2 hots and a neutral. But, power on poles (single phase) comes on one hot, with one neutral (line+neutral).
2. Other lines run 2 hots (line-to-line configuration) no neutral no ground, so lighting arrestors are needed on both lines every ½ mile or so or at critical points like expensive transformers. Line-line systems are being phased out compared to line-neutral - which have better fault-clearing behavior.
3. The pole transformer has primary winding between hot and neutral. Secondary goes to the house. The secondary is center-tapped to provide hot-neutral-hot with 240/120 split phase.
4. The transformer tank (case) is bonded to the neutral conductor and to the grounding electrode. During a fault, the grounding system establishes earth potential for the case, but most of the fault current returns through the neutral conductor because it has much lower impedance than the earth path.
5. Do power poles carry 2 wires - neutral and hot? Yes. Rural has multi-grounded neutrals - neutrals with multiple grounds at bases of power poles.
6. A ground is created by a ground rod at the house, since there is no ground wire coming to the house.

Summary for Transformer Grounding:

1. Lightning arresters dump surges to ground (from line to ground through varistor)
2. Transformer tank cases are grounded.
3. Transformer tank case is bonded to neutral of power grid.
4. If short in transformer - Fault current mostly returns through the neutral, not earth.

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Intro

• 4 types of electrical diagrams
• Single line diagrams show nodes and lines, help understand overall design.
• 3 line diagrams show the 3 wires of single phase AC systems. Can be 4 lines with ground, and 5 lines (A, B, C, Neutral, Ground) for 3 phase.
1. 120VAC has 3 wires - hot, neutral, ground. 240 v has 4 wires - 2 hot, neutral, ground. 3 phase has 3 hot, neutral, ground. Compared to 120V AC, it can carry 3x the power with 1.6 times the wires. 240V carries 2x the power with 1.3x the wires. 3/1.6=1.9, and 2/1.3= 1.5. Power to wires ratio is best for 3 phase, though ‘2-phase’ is more effective than 1 phase.
2. ‘True’ 2-phase does exist. ‘True’ vs 240 ‘2-phase’ - difference lies is in the power generating mechanism.

Required Circuits, Devices, and Dedicated Circuits

• What is the minimum home circuit design?
• What is the minimum marketable circuit design? Are these 2 the same?

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Which Devices must be on dedicated circuits?

1. Vent hood for kitchens if it is plug-in. This is because microwaves end up being added frequently, and they don’t want you to plug in a microwave to a vent hood outlet. Thus, plug in vent hoods must be on a dedicated circuit - so you can plug in microwave later.

Equipment Space Requirements for Hybrid PV Electrical System Components

Space Requirements:

1. Equipment must have 30” or width of equipment in terms of working space side to side. Mount with structural wood screws. Hole saw sizes for knockouts.
2. 6’6” max height to top of main circuit breaker
1. Mount carport CSED as high as possible to keep apparent space more open.
3. Clear space: space in front of equipment is not to be used for storage
4. Associated equipment can be above other equipment, but typically it can’t stick out 6” more than the equipment.
5. No other requirements exist for spacing side to side
6. Only associated equipment can be above or below

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More:

1. About hybrid vs off-grid inverters - hybrids have smaller peak ratings than off-grid, and are less expensive to manufacture.
2. Seed Eco-Home power calculation indicate max power continuous power draw much smaller than the peak power of grid service entrance:
1. Code requirement is about 19.2kW
2. Off-grid inverter has only 6 kW - it is rated for only its max power unlike grid tie, which can pass as much energy as it neds from the grid.
3. DC coupled inverters taka solar DC and charge batteries directly, without going through inversion.

Grounding

1. Double isolation of panels:
1. Panel frames in transformerless inverter systems must be grounded.
2. Mounting Rack must be grounded. In our case it’s not metal.
2. Grounding:
• Ideal ground rod separation is 16-20’ if need multiple rods (earth resistance greater than 25 ohms)
1. Stack Exchange article. If 2 rods, we can use thinner copper for second, as it does only half the current or 100A for a 200A system?
• Junction box and transfer have ground wire connecting to CSED ground rod through CSED terminal
• Exposed ground wire is tucked behind the streed feed conduit, and goes to 2 rods in front of house/carport..

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Typical grid-tie inverter does not pass grid power through the inverter.

Hybrid inverter passes grid power through the inverter.

Bathroom

1. Bathroom is defined as a space with sink, and shower or excreta fixture.
2. Bathrooms require 20A circuit though can use 15A outlet, and GFCI. GFCI must be readily accessible. Outlet cannot be more than 12” above basin.
3. Bathroom GFCI can supply other uses in bathroom, and other bathrooms, but not other rooms.
4. Bathroom must be served by a 20A circuit. All receptacles in bathrooms must have ground-fault circuit-interrupter (GFCI) protection. Outlet must be within 3’ of all sinks, so more than one outlet may be required. Bathroom must have a light and switch. The fan and lights can be on the same circuit as a bathroom outlet (assuming circuit serves only 1 bathroom). GFCI can be wired to protect another non-GFCI receptacle downstream.
1. Where the 20-ampere branch circuit supplies only one bathroom, outlets for other equipment within the same bathroom can be on the same circuit. As long as the circuit feeds only one bathroom, it can supply power to receptacles, luminaires (lighting fixtures), exhaust fans, etc.
5. Use a vent fan for humidity control
6. Another wiring scheme: 2 bathrooms share GFCI 20A circuit. Light and fan are on circuit from adjacent rooms.
• Can a bathroom share circuit from other rooms for its lights and fan? Yes.
7. General note: just look at what is required. If a requirement is not listed, then it’s not required. Only requirement for bathroom is that receptacles must be 20A GFCI and multiple bathrooms can share this dedicated circuit. Nothing else can be on this circuit if the circuit serves more than 1 bathroom. There is nothing that says lights and fan must be on a dedicated circuit - ie, these can be fed from other rooms.

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Hunker Article:

1. Light must be >3’ from rim of shower unless it’s ‘suitable for wet locations’.
2. One dedicated circuit for bath suffices - if no other rooms are served by that circuit.
3. The preferred route for GFCI protection of bathroom is a GFCI outlet feeding lights or fans downstream, as opposed to a GFCI circuit breaker
4. AFCI appears not to be required in bathroom, but GFCI is.
5. 6 foot power cord requirement

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Bathroom Electrical

• Can mount right in light box, about 2”x3” size, for retrofit
• Sample Diagram:

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• Compared to standard method:

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• Take the case of the main entrance 2-way light:
• Needs at least 52 feet of extra 3-wire between switches (thick red line) (sppears even more would be used if we went around the door utility channel)

In sum: quite a savings in wire by using wireless. There is a parasitic load - at 2kwHr cost per year. That is $20 over 100 years - not too bad.

Wireless Switch - How Much Less Wire and Effort?

Light box

Junction Box

Hot Line

Controlled Line

Independent Wall Switch, anywhere

Light box

Junction Box

Wired Wall Switch

2 Way Light

Requres a 2-wire cable to light, and a 3-wire cable between switches

Wireless Switches Advantages and Disadvantages

• Advantages:
• Simplifies wiring significantly, especially for 3-way switches
• Kinetic switches never need a battery
• If system design is good and device is easily accessible, maintenance is low cost
• Because we have an openable utility channel, modifications can be made later at low effort if hard wiring becomes necessary
• Disadvantages:
• Some local codes may not allow it, new to inspectors?
• 2020 NEC was updated to add other listed control devices for switching (in addition to standard hard-wired switches
1. Listed vs UL Listed. It is also not same as ‘approved’ - see more about listed, approved, NEC, NFPA. Also, UL is not CE and vice versa.
2. UL, CSA, and ETL are accepted in the USA as listed

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Options:

1. RunLessWire - ETL listed. $130.
2. Thinkbee no battery not listed. Install in the fixture itself? fixture?
3. Receiver - not listed; separate kinetic switch; no batteries.
1. Kinetic switch included
4. Gennic kit - no battery
5. Thinkbee - not UL Listed; 2kWhr/yr parasitic load (225 mW constant). Battery.
6. Fosmon wall outlet - ETL listed; 2 kW, $20. But has a battery.
7. Light Socket - ETL listed - but has battery.
8. 3 way light kit - has battery.

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Power Meter and Panel

Wiring

Socket

1. Horn Bypass - any bypass will do, whether horn or lever. It’s for power company to continue power supply to house when they are working on the power meter.

PV Wire

• THWN-2 can be used up to 90C and wet environment.
• THHN -
• See PV design for SH4

12-2 ga NM-B,

20 amp

$0.52/ft now 40c

14-2 ga NM-B

15 amp

$0.4/ft !

14-2-2 ga NM-B

15 amp

$1.1/ft

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14-3 ga NM-B

15 amp

$0.50/ft

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10-3 ga NM-B

30 amp

$2/ft

10/2 - $1/ft

12-3 ga NM-B,

20 amp

$1.1/ft now 67c

12-2-2 NM-B,

20 amp

$1/ft

Chest fridge or freezer multiwire circuit

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6/2 NB-B

55 amp

$2.5/ft

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Wire and Cost

• 20A wire is 1.33x the cost of 15A wire - same price
• 14-2-2 saves wiring time as 2 wires are run in one. 5 wire.
• Price is the same per circuit
• More materials-efficient as it shares a ground (compared to using 2 of 14-2 wires (6 wires)
• But - not useful as you can do 14-3 for 2 circuits
• Only required use case: 3-way lights, and more complicated circuits
• 14-3 is used for 240V (2 hots) or for 2 circuits sharing common + ground wires such as lighting circuits.
• Even more efficient than 14-2-2 for running 2 circuits!
• 14-3 circuits with 240V disconnect are thus the easiest way to go - this is the multiwire circuit
• 10-3 30 amp orange $179 at about $3/ft at big box
• Much better online - $111
• $253 for 100’ power cord

Notes:

• You can run 12 ga wire to handle more circuits, or for using a 15A breaker if you want to upgrade to 20 later [ref]
• No maximum external sheath inside box for MM cable.
• Wire sticks out 6” minimum from clamp, and 3” minimum from front of box.

Wire Ampacity

• Wire gets hot with higher current. Limit of wire ampacity is determined by its insulation
• NM-B and UF wires are 60C rated. THHN etc are higher. See chart of ampacity vs temp. Note also THHN vs THWN-2 for PV.
• Ex - Fridge. 500-750W or 4-7A when on. Startup can be 3x, or more. If 3x - inrush current makes it up to 21A - which would exceed 20A 12 ga wire.
• So why does 15A 14 ga work?
• It’s because short-term, the wire can get really hot
• Indeed, NM-B is rated at 90C. Though downrated to 60. See more from this manufacturer.
• Note also that the ampacity of 14 ga is 30A at 90C!
• But - assume up to 6x for LRA (locked Rotor Amps)
• Thus for 7A,would need 42A temporarily
• Wire has PVC (100C melt minimum) and Nylon covering (260C melt)
• This is how 14 ga can handle startup of a refrigerator.

PV Wire - read more. Summary: after combiner, start your conduit. 90C wire is required. Once you enter the house, conduit must be metallic.

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Breakers and Ampacity

• 80% rule for breakers applies to standard breakers - ie, for a continuous load (defined as >3 hrs), can only use breaker up to 80% of its capacity
• On-demand heater is thus exempt.
• This is the same as the 125% rule for upsizing wire in the breaker context
• This is not the same as the 125% rule for wire size in hte wire size context
• NM wire is rated for 90C and 600V, but NEC requires its use at the 60C value
• Insulation is rated for 90C, ampacity is rated for 60C. So NM/B is ‘90/60’ rated, more specifically. It means it will not melt down up to 90C. NEC imposes a safety margin by limiting use to 60C.
• THHN can be used at 90C rating.
• Controversy: Controversy: installation manual says explicitly, 6/2 wire and 70A breaker for the Marey Eco150. It uses up to 60.8A. Thus, breaker is fine. But, is wire OK?
• Look at ampacity table 310.15(B) in the NEC - at 75C, 6 ga wire is rated for 65A. Thus, we are fine.
• What supercedes - manufacturer instructions or code? Code typically trumps, manufacturers may be more strict, or sometimes have more insight. So the case remains biased towards codes, but ambiguity persists. General answer: follow Manufacturer’s Instructions if they don’t violate codes. But that’s ultimately a practical matter for the AHJ.
• 310.15(B) - 60, 75, 90 C values for wire
• Circuit breaker temperature is defined by UL 489 - 90C max breaker temp for normal breakers, and 60C for surfaces that one may touch.
• W

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10-3 ga NM-B

30 amp

$2/ft

10/4 wire

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10/2 wire

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10/4 Wire and Phases

• Single phase is obtained from a single transformer. Transformer can’t convert 1 phase to 3 phase. Needs to know distinction between transforme and converter.
• Multiple phases cannot be obtained from a single transformer. 240V in house is not 2-phase, it’s obtained from a single transformer.
• When do we use 10/4 with Ground? This makes it 5 wire.
• Every box should be founded to ground wire
• But, only service entrance should be bonded
• Bonded means neutral connected to ground
• Significance - neutral should not be connected to ground in the house or breakers may not trip (power goes through ground instead of all through neutral wire) and parts of house may get energized.
• 10/2 with ground - 120V split phase. or 480 split phase or 240V non-split. Typically 120V, one leg of a 240V circuit. Higher amperage on 120V. Not used anywhere in Seed Eco-Home
• 10/3 with ground - 4 wire - 240V 2 phase, with common ground. Separate ground and neutral.
• 10/4 with ground - 5 wire. Common ground, but separate neutral as a non-multiwire way to run 2 circuits in one cable. Each circuit is 120V and has hot-neutral combo. Other applications are multiple-way light switches.
• Conclusions:
• use 10/3 wire for induction cooktop, which gives you a separate ground to the cooktop.
• Use 10/2 wire for heat pump? Yes.
• Apparently, indoor unit also runs at 240 because no neutral is used.

Electrical Design Guide Overview

This is a basic design guide that describes how the Seed Eco-Home 2 electrical system was designed. There are 5 aspects:

1. System Design - Critical components of sound design, energy efficiency, renewable energy.
2. Rules for easy build, modularity - these are logical, practical rules that reduce costs of an equivalent system to about 25% of industry standards using our methods of construction. 50% savings are from smart design, and 50% are from the ability of the owner builder to do the electrical work in the simplest way possible, via integrated design where electrical is not an afterthought to be solved by the electrician - but it is designed explicitly to be integrated into the modular wall panels, in the simplest, quickest-to-build way, while improving performance.
3. Code considerations - following applicable codes for safety and performance standards
4. Usability consideration - safety, convenience, expansion. light for ambience, right amount of light,
5. Calculations - understanding basic capacity and performance characteristics from first principles

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Inverter

PV Panels

Grid

Transfer Switch

MPPT Charge Controller

Breaker Box

Outlets

Fat Pipe

Lights

ExteriorOutlets

Outlets

GFCI Outlets

PV Wiring

PV Mounting

Light Junction Boxes

Utility Channel

Utility Channel Multioutlet Assembly

Breakers

Open Source Power Meter

240V Outlets

4kWhr Nickel Iron Battery Bank

Smart Controller

Heat Pump

Tankless Electric Hot Water

Light - Motion Sensitive

Bathroom Vent Fan

Range Vent Fan

Power Meter

Induction Cooktop

Washer

Dryer

240V Outlets

Design Guidelines

Ute channel

Junction Box

Light Fixture

Lower Level Outlet

Ute channel

cover

Exterior Outlet

Exterior Light Fixture

Upper Level Outlet

Basics of common sense:

1. Use open source hardware in the system - such as Open Energy Monitor and Open Source PV System
2. Use a utility channel, avoid drilling through all the studs. Drilling through studs is unnecessary, time intensive, and it weakens the structure. You have to thread the wire through the studs. This takes a simple tasks of taking a wire from point a to b, and extends this by hours for each run. This is easily designed out from the operation if you want a house that is easy to build.
3. Run the shortest wire lengths possible.
4. Use 15A wire for all loads 15A or less, including 240V
5. Use GFCIs in wet areas - kitchen and bathroom
6. Mount wiring in panels, not during the wiring stage.
7. Extend panel wiring down to bottom to utility channel, and terminate with junction box for connection to wiring in utility channel
8. For doors, run the wiring inside the door trim
9. Wire runs from breaker box, and connect to wire nuts in junction boxes
10. Mount outlets on the utility channel covers
11. Mount lights at upper part of walls
12. Mount light switches in walls.
13. Label wires that are near the utility channel.
14. Special wire needs: Heat Pump, Induction Stove, Microwave, washer, dryer, dishwasher, large TV.
15. Include PV on top
16. Use a power meter from street, with manual transfer switch as a baseline.

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Wall panel

Electrical Numeracy and Calculations

• 5670W Solar - One rooftop of PV holds this much solar power.
1. Can do Heat Pump in summer - summer AC
2. Can do heat pump for cold days - but needs grid for night
3. Full solar operation if:
1. Use superfridge
2. Cook during the day
3. Hot water tank, 1500W, stored during the day, and on-demand heaters otherwise
4. PV strategy - heat water during the day and store it, run heat pump during the day, and don’t work all night.
• 5670W should be sufficient for 100% off-grid during the day. Auto switch to grid with transfer switch at night.
• Minimum Energy Storage for 100% solar - 2 scenarios:
• Summer - all solar. Hot water tank from daytime power, no cooking at night. Just computers and lights in evening take 100W total for 4 hours nightly - 6-10 PM. Can be done with Compressed Air Energy Storage.
• Ryzen 3400G - 65W
• Monitor - 12W
• Lights - 9W LED 60W equivalent, or 2x 5W LED 40W equiv
• 10W for internet router
• Otherwise - a wind turbine can match the CAES in power output - but only when the wind is blowing.
• Small bat banks (30W) can be had for $10 each, so 13 of these give 4 hours of power for $130 in cost. May be a decent solution as these are multipurpose. CAES is a funky solution, which will be ok once optimized, but not without a good air engine.
• Water - 50 gallons will take 4.25 hours with a 1500W heater using the water heating calculator for 120F max temp.
• 100A Grid - 24kW available power with 240V service. That is enough to run 2+ industrial welders: a lot of power. Unless manufacturing or industry is occuring.. Electrical heating should not be used, outside of heat pumps. Max draws at any time are about 11kW.
• Heat pump for heating and cooling - 3kW (12.5A at 240V)
• Electric Water Heater - 1.5kW
• Microwave - 1kW
• Clothes Dryer - 1.5kW
• Washer - 500W
• Hair dryer - 1kW
• Induction stove - 1kW. Electric house heat or electric stoves - wasteful use of energy. Do not use.
• On-demand Heaters are ok for small spaces - 1.4 kW each.
• Expansion - 11kW solar should cover 100% of needs during the day in the summer. AC runs during the day, off at night.

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Zero Energy Operation

• 11kW Solar - 66kWhr max during day allows all energy generation, assuming daytime load peaking
• Inverter - 5 kW inverter from China
• Open Source Arduino Inverter Challenge to be deployed
• Charge Controllers - open source charge controller is useful. For simple battery charging.
• Transfer Switch - includes Smart Home Automation option, base option is a manual, 100A transfer switch.
• Storage to go from low-percentage stored energy at night to full stored energy at night.
• Pumped hydro - but only in land-based locations. Can double up with water recreational facilities, so could be part of any community with 40+ acres.
• Bottom line is water, air, and gas
• Air - 100Whr prototype with off-shelf parts for $300 tank, $300 compressor, $100 air engine, and $100 generator.
• Storage vessels need to be open sourced: composite fiber/polymer tanks
• Hydrogen - open source electrolyzers and composite fiber tanks are needed
• Nickel Iron Batteries - the only lifetime design battery known. $4k/4kW for 30/60 years.

The Code in a Nutshell: National Electric Code

12 ga NM-B,

20 amp

14 ga NM-B

15 amp

You must:

• Use NEC approved wire, no problem. Stores carry it.
• Use correct wire ampacity for your loads. Typical house wire is 15A and goes up from there.
• Have lights in every room. And, they must be switchable either by a wall switch or pull cord.
• GFCI outlets must be used where it’s wet - by kitchen sink or in bathroom.
• Entire house must be grounded with ground rod.
• Every outlet must be grounded.
• Each circuit must be on a circuit breaker.
• Circuit rating for electric motors is 1.25 x their full load (rated) power
• Use protector plates when wire is 1.25” or less from edge of framing member.

Lighting

• According to NEC 210.70, at least one wall switch-controlled lighting outlet (including ceiling fans) must be installed in every habitable room and bathroom of a dwelling unit. In rooms other than kitchens and bathrooms, a receptacle controlled by a wall switch can be used instead of a lighting outlet.
• 2020 NEC says wall-mounted control device - change was made fom 2017 to 2020 NEC to accommodate wireless switches. But it does not appear that pull cords are allowed, likely for fire safety reasons.
• You can install 30 50 watt lights on a 15A circuit. More on a 20A circuit.
• Required lighting support is 3W per square foot. Wiring must support that much, though of course you could use less power once installed. 3000W means 25A of light capacity - meaning 2 15A circuits minimum for lights.

Exterior

• Code - one in front, one in back of house - TR/Water Resistant/GFCI
• Every porch, deck, or balcony requires an outlet

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Locations and Heights

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• See Lighting Design Guide for house and bathroom lighting locations
• More bath lights
• Outlet - a point of connection. Receptacles are one type of outlet. More.
• Heights:
• Wall switch - 48” to bottom of switch
• Porch light - 66” to 72” to center of sconce
• Deck Light - 78-84” - higher than head in order not to blind, not too high so you get good light
• Receptacles - GFCI outlet within 36” of sink, but height not specified
• Kitchen countertop receptacle height - within 20” of cabinet
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NEC for Dummies 1

Taken from llustrated Guide to the NEC - borrow from Archive.org

• Anyone can participate in code updates for the NEC, admisistered by the NFPA (Nat’l Fire Protection Agency
• Branch circuit - a leg coming off the breaker box
• General Purpose Circuit - any combo of lights and receptacles
• Appliance Circuit -
• Individual Circuit - feeds only 1 piece of equipment
• Multiwire Circuit -
• Continuous - 3 hr or more
• 240V circuit must disconnect both legs at the same time when flipped at the breaker panel.
• Allowed wire fill is marked on outlet boxes. The numbers refer to number/gauge. Grounding conductors E count as 1.
• Conduit fill: see table

NEC for Dummies 1

Wire Fill Calculation

1. You can also calculate by summing volume allowance for wires, devices, internal clamps, and grounds (video)
1. Conductors count as one - 10 conductors here
2. Devices count as 2 each - 4 total here (receptacle + switch will go in this box)
3. Internal clamps (plastic tabs holding wire) count as 1
4. Ground wires count as 0.25 - 1.25
5. Total - 16.25
2. Take volume allowance of 2.25 * 16.25 = 36.6
• Box with mud ring is 38 - so we are ok.

Other allowances:

1. GFCI is same as regular outlet (2 in volume allowance)

Mounting with screws on back of box - allowed

Box Sizes:

1. Note that for a pan box - you can mount it without cutting a stud.
1. But, still needs cutout. They have old work versions of these.

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Regular Boxes

Wire Fill Calculation

• Standard 18 cu in box is 2.85” deep
• If we use beadboard, box must stick out ⅜” to match the face of the beadboard
• Ideally we locate box 2” up from bottom, right on top of the blocking
• But, tabs grab up to ⅞” max. Blocking is in the way of tabs.
• Must place the box above the blocking so the tabs fit.123
• To avoid need for added blocking, use studs
1. To avoid conflict with tabs, go 2” above blocking (4” from edge of beadboard)
• Outlet box can also be a junction box
• Junction box cannot be covered
• Must be stapled every 4-6 inches

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Seed Eco-Home Mounting Convention:

1. On a panel looking at the side where box will be mounted:

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• As a default, use the stud second from left to attach the box on the right hand side of the stud, with nails provided or screws
1. Bottom of beadboard cutout is 4 inches above the bottom edge of the beadboard
• If the second stud is not convenient, use any other stud, still at the same height.

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Pre-Marking Box Locations: Don’t

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Transfer marking appears great. Except you need to lift the panel - twice. That works, but why not do better? Mark a panel prior to putting it on the wall - by designing box locations with such efficiency in mind.

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This avoids the common issue of loose, non-flush, or crooked installs. Google ‘are non flush outlets a common problem’ and get 12M results.

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OSE method: mark box locations, run the wire. If the inspector allows you, use old work boxes! Precut the interior sheathing, and staple wire runs + bend such that wire will come out of the precut wall holes in the paneling.

This video shows a retarded and a semiretarded way to locate boxes in panels. A more effective way is to precut the panel if the panel is designed for semi-digital precision. Locate the box after panel is installed. Perfect depth and location is guaranteed. Semi-digital precision = design-for-tolerancing.

Regular Boxes - Old + New Work

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2.25x4.3x2.75

25 cu in

32 cu in

6 lb rating

Use 4” hole saw.

50 lb $2.3. Re clamp - see vid.

50 lb $3.4 Old Work

50 lb pancake; screws only ¾”

Carlon 50lb Old Work

Model B618RR

UPC 00034481100584

Note

No Clamps

Clamps

Note that old work boxes are convenient for 2 degrees of freedom. When mounting, for example on ceiling - an exact depth is required. This could be accomplished by the tab on quick mount boxes. But, this doesn’t address location for wall boxes. D

Quick mount boxes

50 lb rating

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Model B618R

25 cu in

32.5 cu in

Also Amazon. But it’s a unique part. Just do double receptacle there.

Decora edge - lever mechanism

Adapters

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LFC (LFNC + LFMC)

LFNC

LFNC $1.5

LFC

LTNM - liquid tight non-metallic - appears to be PVC both flexible or rigid - but not metallic conduit. LTNM refers to fittings that grab the outside - as opposed teo

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Liquid tight flexible - LFC - can be flexible metallic and flexible non-metallic

LFC

LTNM/PVC

LTNM/PVC

High Amp Outlets

Wire Fill Calculation

Plate here covers entire double box

4.56” wide.

Also comes in 2 screw version.

1. Dryer, range: 4-prong plug for dryer and range
1. Use 10-3 wire
2. Use a double box
3. Use a face plate at end
2. Dryer and range need dedicated outlets
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Youtube Install

Codes for Dummies 2

Support screws must be mounted outside of plastic boxes

Codes for Dummies 3

Non-white is Hot

White is grounded conductor

3-Phase

Split-Wired Receptacle - one side of receptacle is switched

Codes for Dummies 4

240V with standard wire must re-identify the white conductor as Hot

• 3 way light switch can control a light from 2 locations
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• Raceway/Conduit fill:

Codes for Dummies 5

Protection of in-ground wires - conduit, bushing, S curve.

Conduit types

Special Wireways

Options: 1”x2”, 2 , 3 , 4

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NEC for Dummies: Electrical Diagram Example

Note: red indicates codes met

OSE Process:

• Take a screenshot of FreeCAD wall layer of dimensional drawing
• Use various symbols
• Or, use other software to draw out wall lines
• Use Standard House Wiring Diagram Symbols

Example for Rosebud

Don’t put appliances in bathtub. Put light above sink

Code note about bath and shower areas

410.10(D)

Outlets and Lights 1

• See Lighting Design Guide
• Outlet height - bottom of box is 12”+ from top of finished floor. Top of box: 15-48”. Garage is 18” +. Inspectopedia article. Says min 15” above kitchen counters - not. No minimum outsid of ADA.
• All 15/20A house outlets must be AFCI protected. Sourcing.
• The only circuits not needing protection in a dwelling at this time are Bathrooms, Garages, Crawl Spaces, Attics and Outdoor. [source]
• AFCI is not required for 240V appliances
• Heat pump needs GFCI
• Receptacles must be tamper-resistant. Ex.
• 4 20A circuits are required at a minimum - 2 appliance, 1 laundry, one bathroom - + general lighting and general receptacles for a total of 6 circuits.
• Lighting load is 3W/sf)*1000SF = 3000W. That is 25A. For 20A or 15A - 2 circuits are required.
• Water heater circuit breaker over 13.3A (1600W) shall be taken at 150% for breaker size, using the next available size up.
• 15A breakers can’t have 20A duplex receptacles. 20A breakers can have 15 or 20A receptacles.
• Space between receptacles is 12’. Receptacles above 1.7m do not count.
• Bathroom does not appear to count in this rule.
• Receptacles needed within 6 feet on both sides of door (no wires in front of doors)
• Any wall 2’ or longer must have a receptacle.
• Exterior outlet is required at front and back of house, GFCI, max height 6’6” above grade
• All kitchen countertop-servicing receptacles must be GFCI type.
• Weather resistant receptacles are labeled WR. Tamper-resistant receptacles are labeled TR.
• At least one switched light is required per room.
• Switched plug-in light is ok, except kitchen & bath
• At least one switched light is required for every outdoor exit
• Halls also require lights.
• 3-way switch controls lights from 3 locations. 4-way switch controls lights from 3 locations
• Nice video on single pole switch, 3-way switch, and ground-neutral-hot
• Single pole switch can be wired for switch first or light first (With respect to power source). A more complicated version occurs for switch with future-proofing for a light dimmer.

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NEC for Dummies - Kitchen + Heat Pump

• Heat pump must have an outside outlet within 25’ for servicing purposes.
• Kitchen countertops must have outlets every 4 feet (toaster with 2’ cord metaphor)
• No lights, fans, or other rooms fed by kitchen outlets.
• Wall space means back wall space, not side wall if counter ends.
• 2 more receptacle circuits are required at the minimum. Total number for the OSE model is more like 6 kitchen circuits.
• Minimum of 2 20A circuits serves kitchen countertops. Any counter above 12” needs a receptacle. Receptacles serving counters are GFCI. Height max 20”, min is above backsplash
• Island counters require GFCI receptacle.
• Disconnect or breaker lock-in-off-position is required for permanently wired appliances
• Dishwasher can be connected to a receptacle under sink, must be separate circuit. Since 2014, GFCI required. Disconnect is required - a plug can be a disconnect. Such appliances must not exceed 80% of power rating of circuit.
• 2 circuits are required for Kitchen Countertops. These can feed other kitchen-related outlets and receptacles (but not other rooms).
• Plug for dishwasher cannot be behind dishwasher - must be readily accessible.
• There is no location requirement for light switches, but you do need light switches.
• You can have a wireless light switch - but only if that switch is placed permanently in a customary location. This is a safety issue - say your house is on fire or you have guests trying to pinch a loaf. Disadvantage is that you have to use batteries. This is a case for a universal, multipurpose battery. Just one, such as 18650 which can be used for small devices and cars alike.
• Range fan + lights cannot be on the SA circuits. Light requires dedicated circuit.
• Kitchen must have a switch-controllable fixed light, not a plug-in light.
• Range fan, lights, refrigeration equipment must be on separate circuit. Refrigeration can be on 15A circuit. For fridge and freezer, this is just practical: rotten food if another load trips it.
• Stairways require a non-plugged, switchable light fixture.
• Range and dryer at 240V - need ground + neutral wires (4 prong) if these appliances are used.

Remake this for the Seed Eco-Home 2

Kitchen End Walls

• Side wall does not require Kitchen Small Appliance (KSA) receptacle.
• Wall space for KSA circuits means back wall space, not side wall if counter ends.
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Tapping Oven from Induction Cooker

No KSA outlet needed on side wall (front wall of house)

• Stove and Induction Cooker - there is a tap exception rule that allows (2017) 210.19(A)(3) Exception 1 tapping of a larger circuit for an oven.

NEC for Dummies - Hallways, Closets, Attic, Garage

• Hallways have different receptacle rules than walls. Hallways less than 10’ don’t need a receptacle.
• Foyer above 60 sf needs receptacles on each wall that is 3’ or longer.
• Closets cannot have open luminaires.
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• Appliances require disconnecting means.
• Washer requires a designated (not dedicated) outlet, 20A circuit, and GFCI, but receptacle can be 15 or 20A. It seems that if dryer is not 30A 240, then a 240 outlet is not required. Note that modern dryers require a 4-prong plug, 3-prong are no longer allowed.
• You need a light for laundry room/area, from general lighting circuit, which cannot be same circuit as laundry equipment.
• Laundry receptacle must be installed within 6’ of washer, and be no more than 5.5’ above floor.
• Lighting is not required in spaces where there is no equipment that needs servicing.

Garage:

• Garage requires dedicated circuit for outlets, 20A, GFCI/AFCI.
• Dedicated means no other outlets such as lights
• Exception: exterior outlets can be on this circuit.
• Garage door opener receptacle must be GFCI protected
• Garage door opener example
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Load Calculations for Dummies

• General Lighting+Receptacle load is 3W/sf. Thus 3000W, and thus capable of being served by 20A 240 or 15A 240 (15A multiwire circuit)
• Each Small Appliance circuit (there are 2) is calculated at 1500W. 3000W
• A Laundry circuit is 1500W (to serve the washing machine). NEC 210.52(F). “In dwelling units, at least one receptacle outlet must be installed for the laundry.”
• Sum of above is 7500W. (3000+3000+1500). Take the first 3000 at 100% demand factor, and 35% demand factor above that. 0.35*4500=1575.
• Total load for Lighting/Small Appliance/Laundry is 3kW + 1.6kW.
• Other: water heater: 1.8kw, dishwasher (1200W), dryer (1500W in our case)
• Cooking - standard. 4 cooktop. 7kW
• Heat Pump - 2.5kW for 2 ton. 20A circuit, 30A max breaker.
• Largest motor x 0.25 is 2.5kw*0.25 = 625W
• Total of above in bold is is 19.2kW, or 80A (at 240). Can fit all easily on a 100A circuit.
• Expand to 3.125kW for heat pump and add 3kW lights - so this adds 1kW to lights and .625 to heat pump - for a total of 20.8 kW - still under 90A! Keeps to the Seed Eco-Home promise.
• The neutral load defines the imbalance in 2 legs, and sometimes the neutral wire can be smaller than the hots.
• Ground wire size is defined according to load of house.

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Total 80A. Heavy duty dryer: adds 30A at 240 or 110A. This pushes the limits of a 100A breaker box. Note 1 AWG = 110A for 60C rise - is used in standard 100A transfer switch - thus this switch could handle full grid load of house (110A)

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Other requirements:

• Up to 8 outlets on a 15A circuit. A duplex receptacle counts as 2 outlets? No - it’s one (source):
• Receptacle vs outlet - this is one outlet, but 2 receptacles:
• Each breaker can carry only 80% of its load
• 15A breaker - 12A allowed
• General practice: considers 1.5A average load per outlet
• Thus - 8 outlets on a 15A breaker
• In general, one outlet counts as 180W (VA)
• But, it also appears there is no max limit of outlets in residential (commercial only appears to have a limit) - just the load requirement is there
• 15A outlet is ok on 20A circuit, but not 20A outlet on 15A circuit
• For Seed Eco-Home - note that we have 500 sf of space upstairs requires 1500W (3W/sf rule). Thus, a 20A circuit can power this without a problem. There are no requirements for bedroom being on a separate circuit

This is old - now ca have only 8 and 10 15 amp outlets

Condensing and Heat Pump Driers + Induction Cooktops

• Other: water heater: 1.8kw, dishwasher (1200W), dryer (1500W). But, standard load calculations use 5000W for a dryer.
• 6-7 cu ft standard washer size
• Condensing dryers condense via heat exchanger or dehumidifier and are ok, but must be pre-installed.
• Whirlpool 7.4 cu ft
• Samsung 4 cu ft heat pump. Tank or permanent drain
• Note: 5000W or nameplate rating. Note these nameplate ratings are 5000-5600 for 240V
• Are front-loaders more efficient? GE - some top loaders use less power
• Some
• Washer - front loader Samsung 4.5 Steam Energy Star
• Best front-loaders
• Washer-dryer combo $1800 - wha? 120V and no vent?
• Vented - do any come in 20a version? Does a 20A version count for 20A on load calculations, or 30 because of 30A circuit?
• 30A LG 7.4 cu ft $700
• Induction:
• 4 burner - 3700W $900
• Most amazing front loading, combo washer-drier, superefficient, ventless condensing - wash + dry in one - no moving of clothes!
• LG 4.5 cu ft - $1700 min
• Magic Chef 2.7 cu ft $860
• Spruce review

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Design Notes for Dummies

• Wire it multiwire - saves wiring and labor:

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• Note that neutral is wired to ground in main panel, but neutral and ground are not the same wires in any subpanel if any subpanel is connected to main panel.

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• The National Electric Code (NEC) requires wiring in for a washing machine. The National Electric Code, published as the National Fire Protection Association publication number 70A, (NFPA 70A) requires that “In dwelling units, at least one receptacle outlet must be installed for the laundry.” But the next question is, where does the NEC apply? It appears to apply directly in all but 4 states - looking at the International Residential Code - no part states that washing machine plumbing is required. Nor does it mention specific requirements for a washing machine, if it is installed. So it appears that you are required to wire up for a washing machine, but not required to plumb for one when building a house without laundry?
• GFCI not needed for washer unless it’s near a sink, but it is still advisable to use a GFCI due to the presence of water.

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Multiwire Circuit

• Wire it multiwire - saves wiring and labor:

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• Details [source]:
• Multiwire branch circuits, properly configured, offer a number of advantages. Less copper is required (one 12-3 rather than two 12-2s), so there is less material and labor initially. In commercial or industrial work, less raceway fill means additional savings. In residential work, the round three-wire Type NM (Romex) is easier to run and staple than the flat two-wire cable. Less knockouts in the service panel is another plus. Additionally, for long runs there is less voltage drop. Since a multiwire branch circuit is actually two branch circuits, a single run will suffice to meet the Code requirement for two small-appliance branch circuits supplying countertop receptacles in the kitchen of a dwelling. Some electricians run multiwire branch circuits throughout every installation.
• The National Electrical Code permits multiwire branch circuits, but adds requirements to make them safer. Section 210.4(B) states that in the panelboard where the branch circuit originates, all ungrounded conductors must be provided with a means to disconnect them simultaneously. This is usually a double-pole breaker, but two single-pole breakers may be used if they have an identified handle tie.
• Another requirement in Section 210.4(D) is that the ungrounded and grounded circuit conductors are to be grouped by cable ties or similar means in at least one location within the panelboard. This requirement is designed to ensure that the wires will be hooked up correctly, with the ungrounded conductors connected to opposite phases. An exception states that the requirement for grouping does not apply if the circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious.

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Superefficiency

• SEER 26 and 1400W for cooling 1200 sf is the highest efficiency of an air conditioner heat pump
• Senville Aura - current choice - is SEER 21.5
• Higher efficiency costs about $1000 more.
• Lennox SL28XCV Series is SEER 26 in 2400 btu version
• Consider thermal storage totes for night time energy storage

BS Alert

Lots of inaccurate information even on curated sites, here are some:

• The Spruce - ‘2 dedicated circuits for each bathroom’. No. A single dedicated (meaning serving only that bathroom and nothing outside of this bathroom) 20A circuit can serve both outlet and rest of bathroom (lights, fan). Emailed Them.
• Hunker states a ceiling-mounted light is required. Spruce says it can be a wall-mounted light. Which is correct?
• Note that some Amazon sources label certain GFCI breakers as “plug-on design” - but this is not the “plug-on neutral design”. Any breaker with a pig-tail is not a plug-on neutral design, requiring 30% more wiring connections in the breaker panel.

Through-Wall Fan

Standard Options:

• Best fans review
• Hard wired $70 Lowes
• Suncourt, 54 db $56 - lowes
• Quiet
• 4 sone (48 db)
• Silent
• Menards - 8.5 sones
• Lowes

12V Computer Fans:

• 200 mm $13
• 200 mm $15 with LED amazon’s choice
• ​
• Transformer $8

Design Issues:

• Point cooling vents up if grate is low
• See vent grilles

Bonding

• For breakers to trip properly, neutral must be bonded only at main panel.
• See more at Main_Bonding_Jumper. See video below:

Service Entrance Considerations

• Knockout hole sizes table
• 2020 NEC 230.70 requires a service disconnect either outside or inside if power meter terminates directly in a main breaker box with disconnecting means, or a separate disconnect if breaker box is not on the other side of the wall from the meter base.
• 2020 NEC 230.85 requires an emergency disconnect outside for fire safety purposes so the fireman can disable the entire house from the outside
• If the service disconnect is exterior, it can meet the requirements of an emergency disconnect - as long as it is marked as emergency disconnect.
• Whole house surge protector required by 2020 NEC 230.67
• How to Install. Some connect to a circuit breaker, others don’t need a circuit breaker.
• Use a 20-30A circuit breaker, which functions to protect the surge protector itself
• Some whole house protectors have form factor of a breaker, so no other enclosure is needed. But these work with specific brands of breaker boxes.
• Does leviton have one?
• Example of PVC conduit requirement - 200A = 2/0 copper or 4/0 aluminum, and for copper, a 1.5” conduit will do
• NEC table 250.66 shows size of grounding conductor. For 200A, it is 4 ga. Main bonding jumper would be 4 ga as well.
• For any questions, check with AHJ or NHJ.
• Schedule 80 for conduit to meter?
• Wall drilling - studs can be drilled 40% on load bearing walls
• Ground rod sizing table. 4 ga for 200A cable. Ground rod can be ½” if it is listed.
• Temperature of ampacity depends on wet (75C) or dry (90C) location. Thus, interior wire is 90C.
• There are different types of grounds - No. 5019 appears to be equipment grounding conductor,

while No. 5017 appears to be an earth ground.

• Number of wires though a connector: up to 4 8/2 in 1”, up to 8 8/2 in 2”
• ‘Chase nipple’ not code approved.
• Exception is fastened within 12” of outside, only for top entry
• Long discussion
• Arlington NM844 allows up to [10] 12/2 in a 1.25” knockout - (see page 47)
• Conduit types - good buying guide has checklist for all types at Menards
• Why is the neutral smaller in the service entrance? Because it carries unbalanced load at 240V.
• In a 240 only load, there is no neutral wire. Thus, the wire has 2 hots + ground.

Definitions and Myths

• Feeder wire
• PVC conduit fill table
• WIre types:
• URD - Underground residential distribution
• THHN - thermoplastic high heat nylon
• THHN can be run inside walls?
• But I see no posts on XHHW wire (burial cable, X-linked PE, High Heat) running inside walls.
• SER wire - Service Entrance, with Reinforcement tape
• Use SER wire instead of XHHW wire for service feed?
• 125% rule - continuous loads should have a system design sized for 125% of the rated load, such as larger wires or breakers.
• 80% rule - a breaker can be loaded to 80% of its capacity
• Main lug exterior panels are typically used as subpanels. A subpanel must have a separate ground and neutral. Panels are typically designed to function as either main panels or subpanels - see for example install instructions for LR210 or LP212 with explicit mention of main bonding jumper in Fig. 8. Compared to an all-in-one type design - LP315 - the all-in-one has a permanent connection between the ground and neutral, meaning that it can be used only as a main panel - limiting its flexibility.
• Primary and secondary power poles
• Belled end direction of PVC matters for installation. This here appears that utility did it wrong - spigot was installed first?
• Definition of individual branch circuit = dedicated circuit.
• Outlet - any point supplying utilization equipment, meaning either receptacles or hardwired junction boxes
• Volts to Ground: 120v vs 120v to ground - not the same. 240V AC is also 120V to ground, but it is not 120V. When you encounter X v to ground - it could be 2x volts actual.
• 6’ rule for flexible conduit is a myth - applies only to conduit as EGC?