Please help with my home charger install

[bryansocko]

FYI 80% rule that you keep mentioning no longer exists in the code. It has been replaced with NEC 210.19(A). That rule only now applies to continuous loads. A continuous load is defined as continuous draw for 3 hours without interruption.

Realistically the only thing in a house that would be a continuous load would be HVAC, the water heater, and of course the EV charger.

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[Ragman]

Thanks everyone for your help. I think I may go with an outlet instead of hard wiring b/c I probably don't need the extra power...what type of outlet did you guys use and what wire? I was thinking of buying the thicker wire just in case we change our mind in the future...

Do this, many jurisdictions now require an extra permit for hard wired EV Chargers here its an extra $390 - get a 6-50 Nema outdoor rated plug (even if in garage) these are RV/EV rated plugs that are heavier duty. The box will cost $50 and save you potentially a couple hundred.

 

[rdr854]

How large is your house? Your panel already looks pretty full? Unless you have an empty circuit on that panel you might need to install a sub panel just for your garage.

Also note your service to the panel is 200 amps depending on the charger and rate you go up to your close to 35-50% of the capacity. When I charge my truck it's 80amps on the Ford pro charger but always changing at night as not to interfere with other power consumption.

The building department in my county looks at the total load and will not allow circuits to overload the panel. For the sake of safety, they assume that everything is running.

 

[Whammy Bar]

Do this, many jurisdictions now require an extra permit for hard wired EV Chargers here its an extra $390 - get a 6-50 Nema outdoor rated plug (even if in garage) these are RV/EV rated plugs that are heavier duty. The box will cost $50 and save you potentially a couple hundred.

Don't forget that extra 100 bucks you need for the GFCI breaker since you're plugging it in.

 

[bryansocko]

Don't forget that extra 100 bucks you need for the GFCI breaker since you're plugging it in.

Easily close to 200 for some panels

 

[Maquis]

Don't forget that extra 100 bucks you need for the GFCI breaker since you're plugging it in.

He’s in Canada. I don’t think they’ve gone bat$hit crazy with GFCI requirements like we have.

 

[chl]

FYI 80% rule that you keep mentioning no longer exists in the code. It has been replaced with NEC 210.19(A). That rule only now applies to continuous loads. A continuous load is defined as continuous draw for 3 hours without interruption.

Realistically the only thing in a house that would be a continuous load would be HVAC, the water heater, and of course the EV charger.

Um, no.

First, no one (the NEC) has changed the definition of a continuous load or how to calculate it as far as I know. The 80% rule is also referred to as 125% rule because that's the inverse of 80% and you can do the calculation either way if you know what you're doing: wire capacity must be 125% of the continuous load, or, the load should be no more than 80% of the wire capacity.

So if your FCSP EVSE draws 80A, the wire must be rated for 80A x 125% = 100A.
And 100A x 80% = 80A, see? Same difference.

NEC 210.19(A) Minimum Ampacity and Size (for branch circuits) doesn't change the definition of what is a continuous load or how to calculate the minimum ampacity requirement/size.

Examples of continuous loads in you house abound:
Light fixtures, the electric water heater, any fixed electric space heaters, the TV you watch marathons on for over 3 hours, your PC you run all day, the hot tub circulating motor running all day, etc.

AND EVSE's are considered continuous loads.

When you think about it, pretty much almost everything in your house could be a continuous load, which is why you want your breaker box to be within the 80% rule.

You may have branch circuits with a mixture of continuous and non-continuous loads, then:

“Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.”

If the load on a branch circuit is a continuous load and calculated to be 100 A, NEC 210.20(A) requires the OCPD rating to be 125% of the calculated continuous load current. [NOTE: that's the same as the 80% rule]

Some examples the NEC gives for continuous loads:

422.13 Storage-Type Water Heaters. A fixed storage-type water heater that has a capacity of 450 L (120 gals) or less shall be considered a continuous load for the purposes of sizing branch circuits.


424.3 Branch Circuits. (B) Branch-Circuit Sizing. Fixed electric space-heating equipment and motors shall be considered continuous load.


426.4 Continuous Load. Fixed outdoor electric deicing and snow-melting equipment shall be considered as a continuous load.


427.4 Continuous Load. Fixed electric heating equipment for pipelines and vessels shall be considered continuous load.


600.5 Branch Circuits.(B) Rating. Branch circuits that supply signs shall be rated in accordance with 600.5(B)(1) or (B)(2) and shall be considered to be continuous loads for the purposes of calculations.


625.41 Rating. Electric vehicle supply equipment shall have sufficient rating to supply the load served. Electric vehicle charging loads shall be considered to be continuous loads for the purposes of this article. Where an automatic load management system is used, the maximum electric vehicle supply equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.

 

[bryansocko]

Um, no.

First, no one (the NEC) has changed the definition of a continuous load or how to calculate it as far as I know. The 80% rule is also referred to as 125% rule because that's the inverse of 80% and you can do the calculation either way if you know what you're doing: wire capacity must be 125% of the continuous load, or, the load should be no more than 80% of the wire capacity.

So if your FCSP EVSE draws 80A, the wire must be rated for 80A x 125% = 100A.
And 100A x 80% = 80A, see? Same difference.

NEC 210.19(A) Minimum Ampacity and Size (for branch circuits) doesn't change the definition of what is a continuous load or how to calculate the minimum ampacity requirement/size.

Examples of continuous loads in you house abound:
Light fixtures, the electric water heater, any fixed electric space heaters, the TV you watch marathons on for over 3 hours, your PC you run all day, the hot tub circulating motor running all day, etc.

AND EVSE's are considered continuous loads.

When you think about it, pretty much almost everything in your house could be a continuous load, which is why you want your breaker box to be within the 80% rule.

You may have branch circuits with a mixture of continuous and non-continuous loads, then:

“Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.”

If the load on a branch circuit is a continuous load and calculated to be 100 A, NEC 210.20(A) requires the OCPD rating to be 125% of the calculated continuous load current. [NOTE: that's the same as the 80% rule]

Some examples the NEC gives for continuous loads:

422.13 Storage-Type Water Heaters. A fixed storage-type water heater that has a capacity of 450 L (120 gals) or less shall be considered a continuous load for the purposes of sizing branch circuits.


424.3 Branch Circuits. (B) Branch-Circuit Sizing. Fixed electric space-heating equipment and motors shall be considered continuous load.


426.4 Continuous Load. Fixed outdoor electric deicing and snow-melting equipment shall be considered as a continuous load.


427.4 Continuous Load. Fixed electric heating equipment for pipelines and vessels shall be considered continuous load.


600.5 Branch Circuits.(B) Rating. Branch circuits that supply signs shall be rated in accordance with 600.5(B)(1) or (B)(2) and shall be considered to be continuous loads for the purposes of calculations.


625.41 Rating. Electric vehicle supply equipment shall have sufficient rating to supply the load served. Electric vehicle charging loads shall be considered to be continuous loads for the purposes of this article. Where an automatic load management system is used, the maximum electric vehicle supply equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.

I was simply informing you there is no where in the NEC 2020 or forward code that uses terminology "80 percent rule". It is sized by 125 percent as written.

From the 2023 NEC.

Article 100 Definition: Continuous Load: A load where the MAXIMUM current is expected to continue for 3 hours or more.

Is computer a continuous load? No because the power draw does not sustain a maximum load for over 3 hours. A hot tub by NEC definition is still not a continuous load unless every single component of the tub (lights, blowers, etc.) were running simultaneously for more than 3 hours. That is not possible as the blowers and motors have safety timers on them. This is the same reason why a stove is not considered a continuous load even if you use it all day long, the elements cycle off and on.

210.20(A) Continuous and Noncontinuous Loads. "Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125% of the continuous load." Then they give an example in Exhibit 210.24.

Of course an EVSE is a continuous load. It can draw the maximum sustained current for over 3 hours.

I respectfully do not agree with your assessment whatsoever that most of the house can be a continuous load as it's not realistic. If that was the case I would have to add up every single appliance / device in the house and have 400 amp services in 1800 square foot houses. There is overhead for reason. That is why a cl200 service has a 200 amp main breaker. You can use 160 amps continuously and the other 40 amps is non continuous load headroom.

 

[Whammy Bar]

Um, no.

First, no one (the NEC) has changed the definition of a continuous load or how to calculate it as far as I know. The 80% rule is also referred to as 125% rule because that's the inverse of 80% and you can do the calculation either way if you know what you're doing: wire capacity must be 125% of the continuous load, or, the load should be no more than 80% of the wire capacity.

So if your FCSP EVSE draws 80A, the wire must be rated for 80A x 125% = 100A.
And 100A x 80% = 80A, see? Same difference.

NEC 210.19(A) Minimum Ampacity and Size (for branch circuits) doesn't change the definition of what is a continuous load or how to calculate the minimum ampacity requirement/size.

Examples of continuous loads in you house abound:
Light fixtures, the electric water heater, any fixed electric space heaters, the TV you watch marathons on for over 3 hours, your PC you run all day, the hot tub circulating motor running all day, etc.

AND EVSE's are considered continuous loads.

When you think about it, pretty much almost everything in your house could be a continuous load, which is why you want your breaker box to be within the 80% rule.

You may have branch circuits with a mixture of continuous and non-continuous loads, then:

“Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load.”

If the load on a branch circuit is a continuous load and calculated to be 100 A, NEC 210.20(A) requires the OCPD rating to be 125% of the calculated continuous load current. [NOTE: that's the same as the 80% rule]

Some examples the NEC gives for continuous loads:

422.13 Storage-Type Water Heaters. A fixed storage-type water heater that has a capacity of 450 L (120 gals) or less shall be considered a continuous load for the purposes of sizing branch circuits.


424.3 Branch Circuits. (B) Branch-Circuit Sizing. Fixed electric space-heating equipment and motors shall be considered continuous load.


426.4 Continuous Load. Fixed outdoor electric deicing and snow-melting equipment shall be considered as a continuous load.


427.4 Continuous Load. Fixed electric heating equipment for pipelines and vessels shall be considered continuous load.


600.5 Branch Circuits.(B) Rating. Branch circuits that supply signs shall be rated in accordance with 600.5(B)(1) or (B)(2) and shall be considered to be continuous loads for the purposes of calculations.


625.41 Rating. Electric vehicle supply equipment shall have sufficient rating to supply the load served. Electric vehicle charging loads shall be considered to be continuous loads for the purposes of this article. Where an automatic load management system is used, the maximum electric vehicle supply equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.

Someone should take away your keyboard.

Stop providing false and misleading information and go touch grass.

 

[bryansocko]

If you think about it, utility bills would be astronomical if we used more than a few 10s of amps regularly. If someone used 100 amps for 4 hours per day, plus 20 amps for the remainder of each day, that would be 5760 kWh per month. That's about 5 times my highest usage during the summer when I'm running the A/C all the time.

As electricians, we like to install a service that will meet every need without ever tripping a breaker, but in doing so, we waste a lot of resources installing oversize services. I admit I use the standard Load calc method for a new service build. Thinking about the future, it makes my job easier if I come back years or decades later and they want to add a load, and there's still plenty of capacity without upgrading. Over the long term, is that more wasteful than installing a smaller service and then upgrading it decades later when they add a new load? There are a lot of variables to consider when you start asking such questions, and it's easier to just build a new service to meet the standard load calculation result. It's guaranteed to work in maybe more than 99.9% of cases, but that's because it's overkill in more than 90% of them.

Turn on everything you possibly can in the house, plug in the truck then put a CT meter on the service legs, I will bet you do not even hit 50% of the actual realized load vs the standard load calc.

 

[chl]

Someone should take away your keyboard.

Stop providing false and misleading information and go touch grass.

Nothing false there basic math.

I suggest you try using a calculator:

100A x 80% = 80A;
80A x 125% = 100A

Ask any old electrician: The National Electrical Code (NEC) by the National Fire Protection Association (NFPA) 80% rule is a guideline that recommends that circuit breakers should not be loaded to more than 80% of their rated capacity for continuous loads.

 

[chl]

If you think about it, utility bills would be astronomical if we used more than a few 10s of amps regularly. If someone used 100 amps for 4 hours per day, plus 20 amps for the remainder of each day, that would be 5760 kWh per month. That's about 5 times my highest usage during the summer when I'm running the A/C all the time.

As electricians, we like to install a service that will meet every need without ever tripping a breaker, but in doing so, we waste a lot of resources installing oversize services. I admit I use the standard Load calc method for a new service build. Thinking about the future, it makes my job easier if I come back years or decades later and they want to add a load, and there's still plenty of capacity without upgrading. Over the long term, is that more wasteful than installing a smaller service and then upgrading it decades later when they add a new load? There are a lot of variables to consider when you start asking such questions, and it's easier to just build a new service to meet the standard load calculation result. It's guaranteed to work in maybe more than 99.9% of cases, but that's because it's overkill in more than 90% of them.

Turn on everything you possibly can in the house, plug in the truck then put a CT meter on the service legs, I will bet you do not even hit 50% of the actual realized load vs the standard load calc.

Probably true with many (most) residences.
Better safe than sorry - sorry is way more expensive.

 

[bryansocko]

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I have installed 800 amp 3 phase service in mansions. We legitimately turned on everything we possibly could. And we could barely break 100 amps

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