Is it acceptable to run the bonds for multiple separately derived XFMR’s to the ground bar of the main switchboard in lieu of going to building steel. I have received a 50/50 split from other electricians I have asked this. Looking for something definitive.
XFMR Bond at Main switchboard
- Thread starter SteveO28
- Start date
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Where in NEC Section 250.64 (Grounding Electrode Conductor Installation.) have you gathered your information?
JerodMD
New User
- Location
- South Dakota
- Occupation
- Engineering Designer
Yes, you can. It will likely have less impedance than building steel as well.
- Location
- Illinois
- Occupation
- retired electrician
Assuming the bus bar is at least 1/4" x 2", I see 250.64(D)(2)(3) as permitting this. I would permit this connection no matter what the ground bus size actually is.
If the transformers are in locations that would permit, a single 3/0 can be run with taps to the transformers if the installation complies with 250.30(A)(6).
However if structural steel exists in the areas served by the transformers, 230.104(D)(2) will require the steel to be bonded
If the transformers are in locations that would permit, a single 3/0 can be run with taps to the transformers if the installation complies with 250.30(A)(6).
However if structural steel exists in the areas served by the transformers, 230.104(D)(2) will require the steel to be bonded
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Not from me, I think it can be done, but you need to look at the code section to see where the permission is given. Don't believe strangers, look at the code section I referenced.
Have you looked at the article sections Ron and Don pointed you to? It will clear up your question. Listening to others with out a code book in hand is simply hearsay.