grounding bushing?

Status
Not open for further replies.
T

timz

Member
Location
Michigan
Is it necessary to install grounding bushings on the secondary conduits in a seperately derived system such as in a transformer installation.
 
Probably not. You need to provide more details. There are many variables to consider.
 
infinity said:
Probably not. You need to provide more details. There are many variables to consider.
Click to expand...

An SDS is not defined as Service so 250.92(B) would not be applicable. As Trevor mentioned there are other variables, what they are I have no idea. Would one think that the secondary side of an SDS require a bond bushing?
 
You treat it like any other metal conduit installation. You only need grounding bushings on one side of the conduit or the other. Of course your transformer needs to be bonded to the building steal. But, you can do that with a ground lug. Now some building specs. may go above and beyond the code. Wanting grounding bushings every where.
 
buckofdurham said:
You treat it like any other metal conduit installation. You only need grounding bushings on one side of the conduit or the other.
Click to expand...

There is no NEC general requirement to use a bonding bushing on conduit installations.

There are certain times we are required to use bonding bushings, such as services 250.92 or depending on the listing and design of an enclosure 250.97 may require bonding above 250 volts to ground.

Is it necessary to install grounding bushings on the secondary conduits in a seperately derived system such as in a transformer installation.
Click to expand...

Assuming, punched holes, not concentric and / or less then 250 volts to ground then no, the NEC will not require bonding bushings
 
grounding bushings

grounding bushings

The liquidtight conduit is 3inch in size and feeds a lighting panelboard from the secondary of the transformer. they are clean punched holes, no concentric knockouts, 208/1210 volt system. liquidtight conduit provided for flexability.
 
Last edited:
timz said:
The liquidtight conduit is 3inch in size and feeds a lighting panelboard from the secondary of the transformer. they are clean punched holes, no concentric knockouts, 208/1210 volt system. liquidtight conduit provided for flexability.
Click to expand...


Bonding bushings are not required for the installation you've described.
 
In a conduit this large, are there are wires sized #4 or larger? If so, you need a smooth non-conductive bushing on the connector. So if someone said you needed a bushing, perhaps that is what they meant.
 
Status
Not open for further replies.
Top