Service Conductor Distance?

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charlie b

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Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
Re: Service Conductor Distance?

Start with 240.21(B). The secondary of a transformer can be considered a ?tap? for the purposes of this section. The ?Tap Rules? give limits for conductors that are run without an overcurrent device at the tap point. But if you do have an overcurrent device at the secondary of the transformer, there is no limit on the distance from that point to the switchgear.
 

bennie

Esteemed Member
Re: Service Conductor Distance?

How does the feeder from a transformer secondary qualify as a tap?
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
Re: Service Conductor Distance?

I have come across that interpretation - that the Tap Rules can be applied to transformer secondary conductors. I?m no strong supporter of that notion, but I cannot cite a code section that proves it wrong. My main point, however, is that there is no other code section that would restrict the length of the secondary conductors.
 

bennie

Esteemed Member
Re: Service Conductor Distance?

I don't understand how a service feeder can be called a tap conductor.

A service feeder is not limited to a specific length before it hits an overcurrent device.
 

jtb

Senior Member
Location
Pennsylvania
Re: Service Conductor Distance?

Thanx for the info. I guess 'no max distance' is the answer, due to no code reference. I actually try to keep the wires as short as possible, but have to run it a ways this time, and wanted to know for sure.
 
Re: Service Conductor Distance?

Only voltage drop for circuit length seems to be your limiting factor. I know of no limitations on wire size for circuit lengths except where previously noted.
 

sragan

New member
Location
Illinois
Re: Service Conductor Distance?

240.20 C lists the tap rules for transformer secondary conductors. #4 lists requirements that allow for outside taps of unlimited length (see 230.6 for a definition of outside). However, if the conductor are the service entrance conductors or service laterals, article 230 applies instead of article 240, and the utility company rules come into play.
 
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