Bonding in service disconnects and

J

josiahcarlson

Member
Location
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Why do we install a main bonding jumper in each service disconnect 250.24(C) and bond in the ct/meter socket? Wouldn't this create the possibility of objectional current on any metallic raceway between the disconnect and the ct/meter enclosure and also between each disconnect if there are multiple service disconnects.
This seems like it would go against everything we practice anywhere else in an electrical system.


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Yes there can be currents on metallic raceways, whether they are considered objectionable is how we look at it. We have to install a MBJ in the service gear for OCPD operation under a fault. The bonding on the line side of the service gear is not covered under the NEC
 
Service raceways are permitted to be metallic and as long as they are there will be objectionable current. This is one of the few places in the NEC where it is permitted.
 
josiahcarlson said:
Why do we install a main bonding jumper in each service disconnect 250.24(C) and bond in the ct/meter socket? Wouldn't this create the possibility of objectional current on any metallic raceway between the disconnect and the ct/meter enclosure and also between each disconnect if there are multiple service disconnects.
This seems like it would go against everything we practice anywhere else in an electrical system.


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You could chose the option of using PVC between the CT cabinet and the service disconnect. But that's not what your asking about

A lot of CT cabinets are not bonded by the manufacturer in that case you could bring a main bonding jumper back from the neutral in the service disconnect.

That may be an option to look at
 
My question really should have been:
Why do we allow the conduit to be in a parallel path to the neutral conductor between the service disconnects and the ct/meter socket?

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josiahcarlson said:
My question really should have been:
Why do we allow the conduit to be in a parallel path to the neutral conductor between the service disconnects and the ct/meter socket?

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Because we allow metallic service raceways.
 
josiahcarlson said:
My question really should have been:
Why do we allow the conduit to be in a parallel path to the neutral conductor between the service disconnects and the ct/meter socket?

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I always wondered why also. It seems we want to avoid objectionable current but then allow this. Obviously, it must not be too objectionable. hahaha
 
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