cold water bond

[jheeinc]

Here is my situation. Primary service in a mall is 277/480. In the tenants space they are utilizing 480 for HVAC and 277 for lighting. Then we have a transformer that feeds a120/208 panel.

Originally the water for the stores were not individually metered. Over the years the landlord started putting water meters in line with the space and a bonding jumper needed to be installed. In the electric rooms the main gear is to building steel and a cold water bond is in tact

On this last store the electrical inspector said we needed a cold water bond from our transformer to the cold water pipe in addition to the ground to the building steel we already had in place. We argued but he wanted it done.
When he came back to make sure we did what he asked he then said he also wanted a bonding conductor from the junction box were we tapped our feeder that was inside the tenants space to the cold water pipe

can someone tell me why?

 

[nunu161]

I believe the code says if the water pipe is in the vicinity of the transformer you must ground it along with the building steel.

 

[augie47]

250.30(A)(7) would require the transformer ground.
Is the other one you speak of from the 480/277 power ?
What was he asking to be grounded ? The j box itself ?

 

[jheeinc]

I understand a the Trans has to grounded the steel is the closest but why the steel and the water

yes it is from the 480 power

yes from the j box to the cold water

 

[RUWired]

I believe the code says if the water pipe is in the vicinity of the transformer you must ground it along with the building steel.

Thats right, and the inspector is inforceing 250.104(D)1 and 2. If you choose the building steel as the main electrode for the transformer, the water is required to have a jumper either from the steel or from the transformer.

Rick

 

[augie47]

rick, I agree, but what's with the jumper from the jbox to the pipe ??

 

[RUWired]

rick, I agree, but what's with the jumper from the jbox to the pipe ??

You got me on that one if it's on the primary side of the transformer.

Rick

How is the feeder into the tenant space ran. Sounds like you tapped the 480 coming into the space for the transfromer instead of coming from the 480 panel. Maybe the building space needs the electrodes hit and since its a tap ahead of the panel, the inspector is requiring the tapped feeder to hit the required electrodes.

 

[RUWired]

You got me on that one if it's on the primary side of the transformer.

Rick

How is the feeder into the tenant space ran. Sounds like you tapped the 480 coming into the space for the transfromer instead of coming from the 480 panel. Maybe the building space needs the electrodes hit and since its a tap ahead of the panel, the inspector is requiring the tapped feeder to hit the required electrodes.

As per 250.104(A) 1-2-3

 

[augie47]

As per 250.104(A) 1-2-3

I guess. If it's not connected to the service and the conduit is the grounding conductor.
Bit unusual, but sight unseen, good possibility.