EV chargers, Article 220.83, Article 310.12, another residential idiot arguing with the AHJ!

[jaggedben]

It should also fall under "unlikely to be operated simultaneously" in the old wording

I'm not sure what section you're referring to, but I'm pretty sure I disagree. Many people charge their EVs at any time of day, whether or not they should.

 

[jaggedben]

How to calculate a new ESVE load is clear for existing buildings, regardless if not defined as an appliance.

The operative terms "other load not covered", "or load served" in 220.14(A) wont be limited to appliances.

This language doesn't exist in Part IV.

 

[jaggedben]

For EVSEs, 625.42(A) is new in the 2023 NEC. Which I believe added alot of other relevant sections, like an expanded 750.30(C) which references a new 220.70.

Thanks.
I think some weak points are that 625.42(A) doesn't explicitly modify 220, and that 220.70 doesn't apply to Part IV.

 

[tortuga]

I performed a load calculation using article 220.83, and the load came out to 138 amps. The inspector refuses to approve the permit, because when he performed a standard load calculation, it came out to 194 amps, which is both a large discrepancy from the optional method, and also above the rated ampacity of 4/0 aluminum according to 310.16.

Even if you accept his calculation of 194 amps I'd argue the rating of the service is 200A and per 310.12 the ampacity of the service entrance conductors is permitted to have an ampacity of 83% of 200A which 4/0 AL has.

 

[Elect117]

I spent a decent amount of time re-reading through yesterday and I am still unconvinced that 220.40 doesn't apply to parts 3, 4, and 5. It would be weird to just mention those sections in 220.40 and have them not apply just because it was found at the start of part 3.

Regardless, neither 220.82 or 220.83 include it and they state 'that the demand factors shall apply to the following' but only include loads found in chapter 4. Even 220.3's table doesn't include chapters 6,7,8. And it is phrased like only chapter 4 amends 220. As in installing solar wouldn't amend the service conductor calculation. Which I believe we all agree does. (The service conductors shouldn't be less than the solar).

I personally think it deserves the generator treatment where one section is in 400s and the other is encompassed by 700s when interconnection (Back feed) is considered.

I agree that 220 is antiquated. It is based on the old idea of someone can't use every receptacle, light, AC unit, heater, stove, etc. at the exact same time. Which is very true. I just don't think that applies to a EV charger that (without considering continuous factors) will be 48A on a board that if 100% rated is 200A. ~1/4 of the board by itself. Now, do I think that family is pulling close to over 120A without it? No. But I do not think applying a demand factor to the charger does the process justice.

This language doesn't exist in Part IV.

It does. 220.12 (part 2) is mentioned in 220.83(1)(A)

I think it all comes down to interpretation which sucks. "Load calculations shall include the following:" is both limiting you to the prescribed loads of A,B,C,D and excluding EV chargers from it's use. So someone can interpret it to exclude all other loads from the calculation. Or that the demand factors don't apply to EV chargers. But I don't see trying to put the EV charger into an appliance mold. It isn't one.

 

[Elect117]

Even if you accept his calculation of 194 amps I'd argue the rating of the service is 200A and per 310.12 the ampacity of the service entrance conductors is permitted to have an ampacity of 83% of 200A which 4/0 AL has.

While I agree 310.12 says it. I don't know if it is a good idea to install more load than a wire can handle (based someone's calculation).

Again, I don't know if I agree with the AHJ's calculation or the OPs. I am just saying, that if you were to design a service with 220.82 or 220.83 and then try to justify overloading the conductor with 310.12, it is probably not a good idea.

 

[tortuga]

While I agree 310.12 says it. I don't know if it is a good idea to install more load than a wire can handle (based someone's calculation).

Again, I don't know if I agree with the AHJ's calculation or the OPs. I am just saying, that if you were to design a service with 220.82 or 220.83 and then try to justify overloading the conductor with 310.12, it is probably not a good idea.

When they first added whats now 310.12 to the code in 1956 it was a footnote to the ampacity table for aluminum wire and since there were only two current carrying conductors in a residential service or feeder they upped the ampacity of 4/0 AL to 200 Amps. (It originally was from #2 AL - 4/0 AL)
So in a residential installation with only 2 CC's that 4/0 AL can carry 200A continuously.

 

[jaggedben]

I spent a decent amount of time re-reading through yesterday and I am still unconvinced that 220.40 doesn't apply to parts 3, 4, and 5. It would be weird to just mention those sections in 220.40 and have them not apply just because it was found at the start of part 3. ...

What's weird about it? Why do we have optional permitted calculations in the first place and how exactly would you apply 220.40 to part IV? Where do the examples in the annex show anything like what you're talking about? I'm certainly not going to agree with you and I think I'm not alone here.

I agree that 220 is antiquated. It is based on the old idea of someone can't use every receptacle, light, AC unit, heater, stove, etc. at the exact same time. Which is very true. I just don't think that applies to a EV charger that (without considering continuous factors) will be 48A on a board that if 100% rated is 200A. ~1/4 of the board by itself. Now, do I think that family is pulling close to over 120A without it? No. But I do not think applying a demand factor to the charger does the process justice.

I agree. But the code hasn't been ammended to account for that. Not that I've won any fights with AHJs who require the EV to be counted at 100%.

It does. 220.12 (part 2) is mentioned in 220.83(1)(A)

Sorry, but no. We were discussing 220.14, not 220.12. Also the section you cite refers to 'general lighting and general use receptacles' which an EV is not.

 

[wwhitney]

I'd also argue that I do not have to include the 125% demand factor required by article 625.41 because article 220.83 only requires adding the nameplate rating of the appliance.

First, the AHJ is wrong in the scenario in the OP for the various other reasons discussed. But I wanted to address the above statement.

(Almost) nothing in Article 220 addresses continuous vs non-continuous. Whereas other articles refer to the continuous vs the non-continuous load, in particular 215.2 and 215.3. So while Article 220 spits out a single number for a load, since other articles are asking for a break down of that load into continuous vs non-continuous, when applying Article 220 you need to track the inputs to determine what portion of the answer is a continuous load. This should really be made explicit in Article 220, right now it is only implicit.

So the upshot is that if your 220.83 calculation comes out to 138A, you also need to note that 48A of that (*) is a continuous load, and use that when applying 215.3 (the service OCPD is also the OCPD for the feeder supplying all the loads) and 230.42(A)(1).

Cheers, Wayne

(*) Actually, I don't think it's 48A because of the 40% factor in 220.83. It's somewhere between (8kVA/240V) + 40% * (48A - 8kVA/240V) = 39.2A and 40% * 48A = 19.2A, e.g. it could be (48A / total connected load) * 138A. It's problematic that Article 220 doesn't provide us any guidance on how to compute the portion of the load that is continuous. But even if it is 48A, you're fine with a 200A service with 4/0 Al conductors, 138 + 25% * 48 = 150A.

 

[tortuga]

My take is the inspector is arguing you can't use 220.83 becasue it does not account for "other loads not covered", "or load served" like in 220.14(A).

Thanks for all the replies so far guys. This is how I interpret the code (2020 NEC):
Article 220.83(A)(3)(a): All appliances that are fastened in place, permanently connected, or located to be on a specific circuit
Article 100 definition of appliance: Utilization equipment, generally other than industrial, that is normally built in standardized sizes or types and is installed or connected as a unit to perform one or more functions such as clothes washing, air-conditioning, food mixing, deep frying, and so forth.

Electric Vehicle Supply Equipment (EVSE) does not performs a function like "clothes washing, air-conditioning, food mixing, deep frying, and so forth.". If an EVSE is an appliance then different rules might apply to them.

But that's immaterial since his calc came up under 200A and 4/0 AL has an ampacity of 200A per 310.12.

 

[jaggedben]

My take is the inspector is arguing you can't use 220.83 becasue it does not account for "other loads not covered", "or load served" like in 220.14(A).

But to be clear, that's completely illogical. 220.14 is in the section on branch circuit calculations, and is not required to be considered in 220.83.

 

[jaggedben]

First, the AHJ is wrong in the scenario in the OP for the various other reasons discussed. But I wanted to address the above statement.

(Almost) nothing in Article 220 addresses continuous vs non-continuous. Whereas other articles refer to the continuous vs the non-continuous load, in particular 215.2 and 215.3. So while Article 220 spits out a single number for a load, since other articles are asking for a break down of that load into continuous vs non-continuous, when applying Article 220 you need to track the inputs to determine what portion of the answer is a continuous load. This should really be made explicit in Article 220, right now it is only implicit.

So the upshot is that if your 220.83 calculation comes out to 138A, you also need to note that 48A of that (*) is a continuous load, and use that when applying 215.3 (the service OCPD is also the OCPD for the feeder supplying all the loads) and 230.42(A)(1).

Cheers, Wayne

(*) Actually, I don't think it's 48A because of the 40% factor in 220.83. It's somewhere between (8kVA/240V) + 40% * (48A - 8kVA/240V) = 39.2A and 40% * 48A = 19.2A, e.g. it could be (48A / total connected load) * 138A. It's problematic that Article 220 doesn't provide us any guidance on how to compute the portion of the load that is continuous. But even if it is 48A, you're fine with a 200A service with 4/0 Al conductors, 138 + 25% * 48 = 150A.

We've discussed this before, and I disagree. While the logic of your second paragraph is solid, the problem noted in your footnote effectively invalidates any practical application of that logic. I would also argue that as long as the continuous load is less than the 8 or 10 kVA required in an option method, then continuous load is completely inconsequential to any real world consideration. FWIW, none of the examples for Part IV in the Annex include anything for continuous load.

 

[wwhitney]

But that's immaterial since his calc came up under 200A and 4/0 AL has an ampacity of 200A per 310.12.

310.12 would be a lot clearer and simpler to use if it in fact said that it is modifying the ampacity. But it does not say that.

Cheers, Wayne

 

[tortuga]

But to be clear, that's completely illogical. 220.14 is in the section on branch circuit calculations, and is not required to be considered in 220.83.

Do you consider an EVSE to be an appliance? If not then
can we use 220.83(A) if you have loads that don't fit in (A)(1)-(A)(3) ?
If an EVSE is an appliance then do we need a disconnect within sight of it? 422.31

 

[wwhitney]

We've discussed this before, and I disagree. While the logic of your second paragraph is solid, the problem noted in your footnote effectively invalidates any practical application of that logic.

In a contest between "strong logic" and "practical details that make application difficult" I will pick the strong logic every time. The practical details can be worked out, or the necessary rules amended. Sadly, the CMPs do not seem to share this attitude, judging from the response to some of my PIs. : - )

I would also argue that as long as the continuous load is less than the 8 or 10 kVA required in an option method, then continuous load is completely inconsequential to any real world consideration.

In the OP's case, the continuous load is 48A * 240V = 11.5 kVA.

FWIW, none of the examples for Part IV in the Annex include anything for continuous load.

Well, they don't include any EVSEs, do they? They all predate the introduction of EVSEs. So that has little bearing on the current question.

Cheers, Wayne

 

[thescooper]

Do you consider an EVSE to be an appliance? If not then
can we use 220.83(A) if you have loads that don't fit in (A)(1)-(A)(3) ?
If an EVSE is an appliance then do we need a disconnect within sight of it? 422.31

Article 625.43 (2020 NEC) addresses disconnects, and requires that they be lockable in the open position. I install a breaker lock in the panel and that satisfies every inspector I've ran into.

 

[wwhitney]

Article 625.43 (2020 NEC) addresses disconnects

And it says that no disconnect is required for a 48A EVSE on a 120/240V system.

Cheers, Wayne

 

[Elect117]

Sorry, but no. We were discussing 220.14, not 220.12. Also the section you cite refers to 'general lighting and general use receptacles' which an EV is not.

I am sorry. I misread what you said. I thought you were saying part 2 doesn't apply to part 4. Like in a general way.

What's weird about it? Why do we have optional permitted calculations in the first place and how exactly would you apply 220.40 to part IV? Where do the examples in the annex show anything like what you're talking about? I'm certainly not going to agree with you and I think I'm not alone here.

From NEC 2020,
"
220.40 General.
The calculated load of a feeder or service shall not be less than the sum of the loads on the branch circuits supplied, as determined by Part II of this article, after any applicable demand factors permitted by Part III or IV or required by Part V have been applied.

Informational Note:
See Examples D1(a) through D10 in Informative Annex D. See 220.18(B) for the maximum load in amperes permitted for lighting units operating at less than 100 percent power factor.
"

The informational note for examples underneath 220.40 includes the examples used for optional calculations. The branch circuits are calculated based on part 2. The demand factors for feeders and services are applied based on parts 3, 4 and 5.

And it says that no disconnect is required for a 48A EVSE on a 120/240V system.

Cheers, Wayne

I agree. It is the "voltage to ground" that usually gets ya. The voltage to ground on a 120/240 is 120V.

 

[tortuga]

And it says that no disconnect is required for a 48A EVSE on a 120/240V system.

Cheers, Wayne

I am not seeing that 625.43 modified 422.31

 

[wwhitney]

I am not seeing that 625.43 modified 422.31

(A) Since Chapter 6 is permitted to amend Chapter 4, and 422.31 and 625.43 are addressing the same question (disconnects), 625.43 takes precedence over 422.31.
(B) An EVSE is not an appliance or utilization equipment.

Cheers, Wayne