Does NEC 310.15(B)(6) apply to 120v/208v single phase?

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I may certainly be mistaken and do not have a '17 NEC but I think some on the Forum stated '17 added 208...
if so the answer would likely be "depends" :)
 
(B)(6) is the same in 2014 and 2017. (B)(7) had a significant change regarding voltage.
 
Yea, the 2017 allows 208V if it is single phase. I just assumed 3 phase but I see this new section only mentions feeders

For one-family dwellings and the individual dwelling units of
two-family and multifamily dwellings, single-phase feeder
conductors consisting of 2 ungrounded conductors and the
neutral conductor from a 208Y/120 volt system shall be permitted
to be sized in accordance with 310.15(B)(7)(1) through
(3).
Click to expand...
 
Before 2011 ambient temp correction factors was at bottom of each ampacity table, 2011 they were all omitted and those correction factors were placed in 310.15 (B)(2) - and the rest of that section's existing sub components was bumped up one number so what was (B)(6) then is now (B)(7). That section always applied to 120/240 but 2017 did change to allow for 120/208 as mentioned and does only mention feeders. Not too often does a service containing all three phase conductors supply a single dwelling unit anyway.
 
DRGREG said:
Our local POCO lists 208Y/120 volt, 1ph, 3-Wire Service as a secondary power option. It is marked as "limited availability".
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Limited in that there will be a 208/120 three phase supply transformer involved - and it very likely supplies other customers. Will also be 200 amp or less in nearly all cases.

If it only supplies a single customer it won't be offered - they will get 120/240 single phase from a single phase transformer.
 
The last commercial job we did that had a 3ph 120/208v service to it, but, the Power Co. would not allow us to even set a 1ph temporary off of their 3ph service.

All of our Temps were made up for 120/240v 1ph,yet they would not simply feed our temporary with 1ph 120/208v off of their existing pots at the top of the pole.

We had to build a 3ph. temporary with a 3ph meter before they would connect to it.
They didn't care what we did with it on the load side of the meter.


JAP>
 
jap said:
The last commercial job we did that had a 3ph 120/208v service to it, but, the Power Co. would not allow us to even set a 1ph temporary off of their 3ph service.

All of our Temps were made up for 120/240v 1ph,yet they would not simply feed our temporary with 1ph 120/208v off of their existing pots at the top of the pole.

We had to build a 3ph. temporary with a 3ph meter before they would connect to it.
They didn't care what we did with it on the load side of the meter.


JAP>
Click to expand...
So set a three phase meter socket and come off load side to a single phase panel.
 
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