22kw generator SER cable

[Fordean]

Double checking on 2-2-2+g ser for this unit?
Gen is on one side of dwelling run thru house terminate to other side ats Service on this side is 200 Will use load shed devices on certain items

 

[JoeStillman]

Ok if its copper. If AL, your #2's are only good for 90A, but the genny has a 100/2.

 

[Fordean]

Ok if its copper. If AL, your #2's are only good for 90A, but the genny has a 100/2.

Yes 100

 

[Fordean]

Going to use the tc tf Gen cable Trying to confirm size And cost difference Any brand recommendations? And size Looks like
3-3c plus controls

 

[pipe_bender]

Going to use the tc tf Gen cable Trying to confirm size And cost difference Any brand recommendations? And size Looks like
3-3c plus controls

I have used this its nice, I prefer CU for a genny, easier to install often wire bending space is limited so smaller wire is better;

https://www.prioritywire.com/specs/TC-ER-JP%20Generator%20Cable.pdf

 

[Fordean]

I have used this its nice, I prefer CU for a genny, easier to install often wire bending space is limited so smaller wire is better;

https://www.prioritywire.com/specs/TC-ER-JP%20Generator%20Cable.pdf

Ty

 

[Master Nater]

why wouldn't the Table 310.12(A) dwelling derating factor apply? call it 100a feeder, and you're good on #2 alum.

310.12(C) - in no case shall a feeder for an individual dwelling unit be required to have an ampacity greater than that specified in 310.12(A) or (B).

 

[wwhitney]

why wouldn't the Table 310.12(A) dwelling derating factor apply? call it 100a feeder, and you're good on #2 alum.

310.12(C) - in no case shall a feeder for an individual dwelling unit be required to have an ampacity greater than that specified in 310.12(A) or (B).

That works if the service or main dwelling unit feeder is only rated 100A. If it's rated higher, then the value specified in 310.12(A) or (B) is larger than 100A, and you can't use 310.12(C) for a 100A feeder.

Cheers, Wayne

 

[Master Nater]

there, i found it. 115% rating on generator feeds unless overload protection as required in 445.13.

22000w/240v = 91.667a * 1.15 = 105.41a. = #1 awg alum or 3 cu after table 310.12(A) derating.

i am not sure what wwhitey is referring to. 310.12(B) applies to dwelling feeders 100a-400a. that's why i said "call it a 100a feeder" as opposed to just calling it a 91a. but it has to be rated for at least 106a due to 445.13. table applies, unless you see something i do not.

 

[wwhitney]

i am not sure what wwhitey is referring to.

I am just responding to your invocation of 310.12(C). The OP states a 200A service. So 310.12(C) is only useful for sizing feeders rated at 200A. It does not apply to a feeder of smaller rating.

Cheers, Wayne

 

[Master Nater]

I am just responding to your invocation of 310.12(C). The OP states a 200A service. So 310.12(C) is only useful for sizing feeders rated at 200A. It does not apply to a feeder of smaller rating.

Cheers, Wayne

i don't see it that way. the utility-provided service is 200a. sure. and the house calculated load is above. sure. but i see nowhere in 310.12 that applies to any of that.

the requirements of 310.12 and 310.12(B) are:
- single family dwelling (check)
- single phase 120/240v (check)
- feeder rated 100-400a (check, 106a)
- feeder must supplying entire dwelling unit load (check, the generator WILL be supplying the entire dwelling unit)
- no adjustment/correction factors (??? i'm guessing it falls out under the 445.13 req for 115% for generator feed)

my guess is the final requirement of 310.12(B) drops it out due to 445.13 requring a 115% factor. but i am having a hard time following the rest of your line of thinking.

therefore, without 310.12 derating, and including the 115% factor, this now puts the ampacity required at 106a. therefore 1/0 alum or #2 cu. not #1 alum or #3 cu.

 

[wwhitney]

i don't see it that way.

Ah, I misunderstood what you were saying. I agree that if the entire load is supplied via an automatic transfer switch, and the calculated load of the dwelling unit is 100A or less, and the two sources for the transfer switch are a 200A service, or a 100A feeder from a generator, then the service can use 310.12(A), and the generator feeder can use 310.12(B).

No comments on Article 445, I'm not familiar.

Cheers, Wayne

 

[don_resqcapt19]

there, i found it. 115% rating on generator feeds unless overload protection as required in 445.13.

That only applies between the generator output terminals and the first OCPD. The first OCPD is typically part of the generator unit and the conductors are sized to the rating of that OCPD.

 

[Birken Vogt]

Will use load shed devices on certain items

IMO if you have to use load shed to get below 100 amps then the residential undersizing should not apply. Since the amount of continuous load or load factor placed on the conductors is higher.

 

[pipe_bender]

If your doing generators under the new 2023 code they made it more difficult to use load shed, fewer load sheds are allowed see 702.4(2) . A dealer I spoke to said the Generac 'load shed relays' they sell at big box stores are not article 750 energy management systems, but he is trying to sell energy management systems LOL.
And they tightened the rules on generator sizing, under the old code we could to use a excel spreadsheet from the dealer but now you need a proper article 220 load calc which the dealer wont do unless they are a EE or and EC.

 

[Birken Vogt]

And they tightened the rules on generator sizing, under the old code we could to use a excel spreadsheet from the dealer but now you need a proper article 220 load calc which the dealer wont do unless they are a EE or and EC.

Who is "they" in this case?

 

[pipe_bender]

Who is "they" in this case?

The NFPA I guess its in the 2023 NEC article 702, at one point it said calculated load but did not say how you calculated it, now it says article 220 load calculation, and it also references article 750. It never did that before.

 

[Birken Vogt]

The NFPA I guess its in the 2023 NEC article 702, at one point it said calculated load but did not say how you calculated it, now it says article 220 load calculation, and it also references article 750. It never did that before.

I've always done it by an Art. 220 spreadsheet, but it still says other approved methods, and also in 220 IV it still seems to allow 1-year poco or 30-day self recorded demand data.

 

[Seven-Delta-FortyOne]

For Generac generators, if I'm going underground I use TC/ER GenPro generator cable.

Gen-Pro LLC TCERJP26+2 3x2CU 9 Wire 2500FT :: Tray Cable, #2/3 Copper, 26 kW LP, 2500' :: PLATT ELECTRIC SUPPLY

Tray Cable, #2 Copper, #8G, #18/9, 26 kW LP, 600 Volt, Gray PVC Jacket, 2500', Cat #: TCERJP26+2 3x2CU 9 Wire 2500FT, Mfr: Gen-Pro LLC

www.platt.com

It's direct burial rated, and comes with all the control wires color coded for Generac.

Only reason I don't use it above ground much is conduit fill requirements, which would necessitate a 2" conduit, I believe, based on my last calculation, and nearly all air-cooled generators have 1 1/4" pre punched knockouts, and sometimes getting a 2" in there can get tight.

Besides, I hate trying to pull cable assemblies through conduit.

For a 100A OCPD, I use #3. If I'm installing a generator with a 100A OCPD, it's usually because there are pretty significant loads in the house, and I don't see any reason to downsize the wiring 1 size, using 310.12. While I agree it's allowed, the minuscule savings in wire cost isn't worth not being able to use the full capacity of the generator.

 

[Birken Vogt]

You are one of the only people I know of who direct bury anything. Around here it is just never done. Not saying I am against it. You just don't see it.