System bonding jumper

Status
Not open for further replies.
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I am looking at NEC 2017 Section 250.30(A)(1)(a) which says the system bonding jumper shall connect the grounded conductor to the supply side bonding jumper and normally non current carrying metal enclosure

NEC 2017 handbook exhibit 250.15 shows system bonding jumper connecting grounded conductor, supply side bonding jumper, metal enclosure and primary equipment grounding conductor. Please see below. However the primary equipment grounding conductor is not mentioned to connect in 250.30(a)(1)? Does anyone know whats going on?


cf9671500b0abf83026e38e5a2fe9f73.jpg
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The "equipment grounding conductor" shown is the primary equipment ground. It does not necessarily connect to tht terminal block, in fact, it may not be a wire type conductor at all.
250.30 doesn't mention "A-B-C" either but what is shown is a standard method of wiring the transformer
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Good point on the bond bushings,
Just to mix it up a bit;
If your ECG from the 480 side is a wire type sized per 250.66 for the secondary all the way back to the service you can omit the bond shown to building steel.
250.30(A)(5) Exception 1 and
250.121 Exception
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Disregard my last comment, I was thinking of these all in one things that have a transformer and a panelboard, I think thats Exception 2
 
Status
Not open for further replies.
Top