Grounding a ct cabinet

[dean4766]

Do we need to ground a cabinet containing the ct’sfor a 800 amp service with two runs of 600 mcm, the conduits in and out of this cabinet are pvc, a reputable inspector in Denver says no, although this is not in jurisdiction and he won’t be the one inspecting it, I think it needs to be grounding to eliminate electrical potential, this cabinet is exterior mounted

 

[Dennis Alwon]

I believe all metal parts of the electrical system must be bonded so why would he think you don't need bonding. You just jump from the box to the neutrals.

 

[infinity]

You

Do we need to ground a cabinet containing the ct’sfor a 800 amp service

What do you mean by "ground", using a GEC to an electrode? Typically you just bond it to the neutral.

 

[dean4766]

No not a gec, but bonded, and he says that’s the cabinet is the public utilities and so we don’t have do anything, which I disagree, I wasn’t sure we could bond the can to the neutral at that point since code requires that at first point of service disconnect, but I would agree that is the best solution

 

[Dennis Alwon]

Inspector may be saying you don't have to bond because he knows the power company will do it. I always put the appropriate size bond to a lug and left a few feet for the power company to connect .

 

[electrofelon]

I wasn’t sure we could bond the can to the neutral at that point since code requires that at first point of service disconnect, but I would agree that is the best solution

Everything upstream of the service disconnect is bonded to the neutral (grounded conductor).

 

[infinity]

Everything upstream of the service disconnect is bonded to the neutral (grounded conductor).

I agree, and with PVC raceways there must be a connection between the CT cabinet and the neutral otherwise the cabinet could become energized.

 

[garbo]

We were taught to always ground every metal box that has over 24 volts in it. Extremely important to ground all metal boxes in damp or outdoor enclosures. At one location they had a ungrounded metal pull box where somebody added a few pushbuttons that feed 480 volt starter coils . Because of it being in a damp location did not take long before people reported getting shocked. European companies believe we're the first ones that installed a ground wire from metal box to all hinged cover doors. No better piece of mind then the proper size copper ground &/or bond conductor.

 

[texie]

The inspector is wrong. Send him for more training. All metallic items ahead of the service disconnect must be bonded in a manner compliant with 250.92. Leaving a CT can unbonded is incredibly dangerous and just waiting to kill somebody or potentially start a fire if fed from a grounded system.

 

[tom baker]

My POCO has detailed drawings showing the bonding of the CT cabinet