Compliant Tap?

[BadLarry]

Hi everyone, to give a little background I did 15 years of commercial and some industrial electrical work but most of the engineering was already done for us. Then I went on to start a residential electrical service contracting company 10 years ago. So I don’t have much practical experience with the tap rules. I would like to check my work before I call for inspection. I greatly appreciate your help letting me know if this is code compliant.

I came out of this 200 amp service disconnect with #6 cu. I installed a 60 amp breaker in the enclosure. I believe this is all compliant, but I’m eager to hear your opinions.

-To clarify a few things, this is the third generation Tesla wall connector which has a maximum charge rate of 48 A requiring a 60 amp circuit. This isn’t one of the older ones that had a maximum of 80-100A circuit.
-I realize that I forgot the plastic bushing on the PVC MA right after taking the picture, so that is fixed.
-I understand that it might not be compliant to put a PVC MA into a hub, but that is accepted here and very common.

What are your thoughts?

 

[infinity]

From what I can see in the photo it looks fine except for the large solid bare conductor in the raceway which cannot be larger than #10.

 

[BadLarry]

Thank you for the reply!

That bare conductor is a piece of number 10. I believe that is adequate for 60 A.

What code article would prevent me from using larger than number 10, out of curiosity?

 

[BadLarry]

I have an additional question but I am not able to edit my post.

I used #6 for the tap conductors, now I am second guessing that. My understanding is that they have to be 1/3 of the ampacity of the 200A OCPD, which is 66.6A. #6 is good for 65A under the 75 degree column. I guess I was rounding up as we are allowed to for the next standard breaker size, but I doubt that applies here.

Should I have used #4?

 

[ptonsparky]

I would consider that an outside tap. You’re good.

 

[infinity]

The #10 looks bigger in the photo but then it's good.

 

[ramsy]

Nice mechanical demonstration of 10 foot tap rules 240.21(B)(1), which requires 1/10 capacity for taps. Although, we can't see where #10 terminates in main disconnect?

Did you complete the 220.83 load Calc before adding this additional load? If planning department didn't ask for this, the inspector should.

 

[BadLarry]

Thanks for the replies.

I found the reference to solid bare #10 not being allowed in conduit, I overlooked the "solid" in infinity's post.

The #10 does not terminate in the main disco, my understanding is that the tap rules would require it to be #6 if I was to run a conductor EGC. But since I had the rigid offset nipple solidly connecting the two enclosures, I just let that be the EGC.

As for the load calc, I would be happy to do one if the inspector asks, but he won't- they never do. We have natural gas here in NJ, 200A is plenty for the house plus the charger. I used to do load calcs for the first hundred or so vehicle chargers I installed, but no inspector ever asked so I stopped and figured I would do it on request.

Now if it's a very large house with multiple central AC units, hot tub, etc. I will do the load calc just to determine if I have to lower the charge rate.

 

[ramsy]

250.92(B) would require bonding jumpers, with oversized concentric KO's.

Can you share requirement for #6 ECG on that 60A disconnect?

 

[electrofelon]

250.92(B) would require bonding jumpers, with oversized concentric KO's.

Can you share requirement for #6 ECG on that 60A disconnect?

The offset nipple contains a feeder not service conductors so 250.92 does not apply.

Because its a tap, a wire EGC would need to be sized for the OCPD ahead of the tap conductors which would be #6 CU.

 

[BadLarry]

250.92(B) would require bonding jumpers, with oversized concentric KO's.

Can you share requirement for #6 ECG on that 60A disconnect?

250.92 is for Services, this tap is on the load side of the Service Disconnect.

My understanding is that the EGC of the tap has to be sized to the OCPD that is feeding it, but not larger than the tap conductors. That is where I assumed it had to be #6.

 

[ramsy]

See there, now I have learned something today. Thanks for posting.

 

[BadLarry]

I am glad that I joined here. I posted at another forum asking about this before doing the job and they mocked me, insulted me, insulted my customer, called me a GC, handyman, helper, etc.

Thank you for having a professional forum to learn about code and the trade.

 

[wwhitney]

The offset nipple contains a feeder not service conductors so 250.92 does not apply.

Part of the language of 250.92(B) is "service equipment" and "service conductor enclosures". So is there an argument that it applies to one end of the offset nipple? Not that I see any upside to applying it to just one end of the offset nipple.

Cheers, Wayne

 

[infinity]

The offset nipple contains a feeder not service conductors so 250.92 does not apply.

Because its a tap, a wire EGC would need to be sized for the OCPD ahead of the tap conductors which would be #6 CU.

The #10 is on the load side of the tap conductor OCPD so that is good but the line side of the OCPD would require a #6 as you've stated or just the offset nipple as the EGC.

 

[electrofelon]

Part of the language of 250.92(B) is "service equipment" and "service conductor enclosures". So is there an argument that it applies to one end of the offset nipple? Not that I see any upside to applying it to just one end of the offset nipple.

Cheers, Wayne

If you just look at 250.92(B) then yes I could see that argument being reasonable. However if you look at 250.92(A) it is more clear that it applies to raceways that enclose service conductors.

 

[Dennis Alwon]

Thank you for the reply!

That bare conductor is a piece of number 10. I believe that is adequate for 60 A.

What code article would prevent me from using larger than number 10, out of curiosity?

310.106(C)

(C) Stranded Conductors. Where installed in raceways,
conductors 8 AWG and larger, not specifically permitted or
required elsewhere in this Code to be solid, shall be stranded.

 

[infinity]

If you just look at 250.92(B) then yes I could see that argument being reasonable. However if you look at 250.92(A) it is more clear that it applies to raceways that enclose service conductors.

I agree with the second part, anything on the load side of the service disconnect can ignore the service conductor rules.

 

[electrofelon]

I agree with the second part, anything on the load side of the service disconnect can ignore the service conductor rules.

I do think the structure of 250.92 is poor. (A) tells you what needs bonding, and (B) is the how or what qualifies. They seem to re-state what is in (A) in (B) with slightly different wording. (B) should just reference "the items in (A)" or some such thing.