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Parallel Conductors - extreme example thought experiment

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Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
250.122(F)(1)(b) says the EGC in each parallel conduit must be sized per table 250.122 based on the setting of the OCPD. 700kcmil copper EGC in this example.

However, 250.122(A) says the EGC shall not be required to be larger than the circuit conductors supplying the equipment.
 

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
So what about the size of parallel ungrounded conductor per conduit. If it’s to be sized based on the largest ungrounded conductor is this based on the total sum of largest paralleled conductors feed or the individual largest conductor within a section of conduit in parallel?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
So what about the size of parallel ungrounded conductor per conduit. If it’s to be sized based on the largest ungrounded conductor is this based on the total sum of largest paralleled conductors feed or the individual largest conductor within a section of conduit in parallel?
The sum of the ungrounded conductor size IS the ungrounded conductor size. i.e. 34 sets of #1/0 kcmil, ungrounded conductor is for this discussion is 34*1/0.
 

Jpflex

Electrician big leagues
Location
Victorville
Occupation
Electrician commercial and residential
The sum of the ungrounded conductor size IS the ungrounded conductor size. i.e. 34 sets of #1/0 kcmil, ungrounded conductor is for this discussion is 34*1/0.
The sum of all parallel ungrounded conductors would also determine the size of supply side bonding jumper if this were a separately derived system and system bonding jumper for a service?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The sum of all parallel ungrounded conductors would also determine the size of supply side bonding jumper if this were a separately derived system and system bonding jumper for a service?
Maybe and yes. Once you exceed the values in T250.102(C)(1) the 12.5% rule would apply. For SSBJ's in parallel raceways on a transformer secondary they're sized according to the conductors within each parallel raceway not the total of all of the conductors.
 
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