208/120V service and fdr bushing

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hhsting

Senior Member
I have 208/120V three phase system

Two questions:


1. For downstream of service equipment FEEDER conduit ground bushing according to NEC 2014 are we not suppose to bond to ground bus with conductor? We use Table 250.102(C)(1) for bond conductor size?

2. Also in service equipment incoming are service conduit I understand that service conduit need ground bushing bond to ground bus but outgoing in service equipment are feeder conduit. Should those outgoing conduits in service equipment require ground bushing and bond to ground bus? I looked 250.94 but still confuse
 
I have 208/120V three phase system

Two questions:


1. For downstream of service equipment FEEDER conduit ground bushing according to NEC 2014 are we not suppose to bond to ground bus with conductor? We use Table 250.102(C)(1) for bond conductor size?
raceways less than 250 volts to ground to not require bonding bushings (except those enclosing service conductors), but you can use them if you want. See 250.102(C) for sizing
2. Also in service equipment incoming are service conduit I understand that service conduit need ground bushing bond to ground bus but outgoing in service equipment are feeder conduit. Should those outgoing conduits in service equipment require ground bushing and bond to ground bus? I looked 250.94 but still confuse
No, feeder and branch conduits to not require additional bonding if under 250 volts to ground.

Note there are other options besides bonding bushings, such as bonding locknuts. Everyone seems to go for bonding bushings not sure why, they are a pain.
 

hhsting

Senior Member
raceways less than 250 volts to ground to not require bonding bushings (except those enclosing service conductors), but you can use them if you want. See 250.102(C) for sizing

No, feeder and branch conduits to not require additional bonding if under 250 volts to ground.

Note there are other options besides bonding bushings, such as bonding locknuts. Everyone seems to go for bonding bushings not sure why, they are a pain.

Ok but I thought for feeders conduits downstream of service disconnect one uses NEC 2014 Section 250.120(D) to size bonding jumper from ground bus to ground bushing? Your saying 250.102(C)(1)? I don’t follow
 
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