double pole 120, What are the code violations?

[mbrooke]

I just inspected and did some service work on a old building with non standard configurations for 120v power. Ive never encountered this before. There are several through out.

Conduit comes in to 1 phase 15 or 25kva transformer fed from a 480 volt 2 pole breaker. 480 to H1 andH2. #4/0 copper leaves X1 and goes to second conduit. #8 EGC from 1st conduit bonds to case and then connects to X2. From X2 comes another 4/0 with white stripe and a green #2 that too goes into second conduit. So far a Typical set up no code issues.

Here is where it gets odd:
Conduit then goes into a 225amp panel some with a 200amp main breaker. 4/0 from X1 goes to the first lug/bussbar. 4/0 from X2 to second lug/bussbar. #2 green goes to what is normally the neutral bus and is bonded to the frame. 20amp Double pole (black on top white on bottom pole) breakers pluged into bus bars and branch EGCs landed to neutral/gr buss

Checked polarity on all branch neutrals and surprisingly was all correct. Installer even put a label inside the door "120v only, no shared commons"

These panels feed 120volt outlets and some 120volt lighting.

Other than being a non standard, what codes is the facility violating? Is it safe? When I go back should I change these? :?

 

[hurk27]

I just inspected and did some service work on a old building with non standard configurations for 120v power. Ive never encountered this before. There are several through out.

Conduit comes in to 1 phase 15 or 25kva transformer fed from a 480 volt 2 pole breaker. 480 to H1 andH2. #4/0 copper leaves X1 and goes to second conduit. #8 EGC from 1st conduit bonds to case and then connects to X2. From X2 comes another 4/0 with white stripe and a green #2 that too goes into second conduit. So far a Typical set up no code issues.

Here is where it gets odd:
Conduit then goes into a 225amp panel some with a 200amp main breaker. 4/0 from X1 goes to the first lug/bussbar. 4/0 from X2 to second lug/bussbar. #2 green goes to what is normally the neutral bus and is bonded to the frame. 20amp Double pole (black on top white on bottom pole) breakers pluged into bus bars and branch EGCs landed to neutral/gr buss

Checked polarity on all branch neutrals and surprisingly was all correct. Installer even put a label inside the door "120v only, no shared commons"

These panels feed 120volt outlets and some 120volt lighting.

Other than being a non standard, what codes is the facility violating? Is it safe? When I go back should I change these? :?

Sounds like a attempt to stop stray voltage from the electrical in the barn, this would be my best guess, seen this done at marinas to stop dissolving aluminum boat hulls.

The problem is if the stray voltage is on the service grounding then it does not stop it, because the code requires a EGC run with the 480 volt feeders and the grounding after the transformer is required to be bonded to this EGC.