unfused power

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nietzj

Senior Member
Location
St. Paul, Minnesota
Occupation
Electrician
I'm looking at a set of drawings that show me directly tapping into the existing bus of an old switchboard. Every breaker has been taken so this is the only option. The issue is the plan shows me running about 8 ft before I get to a 600amp fusable disconnect located on a adjacent wall just outside the electrical room. The main switchboard is protected with a 1600 amp breaker. To me the 8ft run is basically un-fused or should be sized to the main breaker at 1600 amps.
please help
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
nietzj said:
I'm looking at a set of drawings that show me directly tapping into the existing bus of an old switchboard. Every breaker has been taken so this is the only option. The issue is the plan shows me running about 8 ft before I get to a 600amp fusable disconnect located on a adjacent wall just outside the electrical room. The main switchboard is protected with a 1600 amp breaker. To me the 8ft run is basically un-fused or should be sized to the main breaker at 1600 amps.
please help
Click to expand...

What you are talking about is called a tap and the rules for such are found in 240.21.

It sounds like it could meet the rules.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
nietzj said:
Yes, the drawings mention a max distance of 25ft so that must be the exception.
Thanks
Click to expand...

Keep in mind that the EGC run with this tap must be sized based on the 1,600 OCPD not the 600 amp until you get to the load side of the 600 amp switch.
 
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