25 ft tap rule

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russ44280

Member
Location
cleveland,ohio
What is your opinion on the following:

We have a panel fed from a 100A fused disconnect in a MCC. The #2 wires are landed on a distribution block which then feeds 3 sets of of 3 40A fuses with #6. From the fuses to another distribution block (#6) and then out of the panel (using #8) to multiple panels that have 30A disconnect switches properly fused, largest load is 17.5A, most between 2.5 and 5A. Our customer's Engineer says we are violating the 25 ft tap rule which I dispute. Any help would be appreciated.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
What is the length of the 3 sets of #6 AWG conductors feeding the 40 amps fuses? The #8's are protected at 40 amps so their length does not matter since they are not tap conductors.
 

russ44280

Member
Location
cleveland,ohio
(I previously posted #6, this was incorrect)

To make it clearer:

#2 leads from 100A fused disconnect in MCC to a remote panel landing on a distribution block, then #8 leads from distribution block to the 40A fuses and #8 leads from the fuses to another distribution block, then feeding multiple panels with fused disconnects from this panel.
From the Distribution block where the #2 leads land to the fuses are 1 foot and from the fuses to the next distribution block is also 1 foot.

Thank you in advance
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
(I previously posted #6, this was incorrect)

To make it clearer:

#2 leads from 100A fused disconnect in MCC to a remote panel landing on a distribution block, then #8 leads from distribution block to the 40A fuses and #8 leads from the fuses to another distribution block, then feeding multiple panels with fused disconnects from this panel.
From the Distribution block where the #2 leads land to the fuses are 1 foot and from the fuses to the next distribution block is also 1 foot.

Thank you in advance

I see nothing wrong with you installation. Your tap conductors are the ones that go from the first distribution block to the 40 amp fuses. They are permitted to be up to 25' in length due to the 25' tap rule. {240.21(B)(2)}

The #8 conductors after the fuses are not taps unless their ampacity has been derated.
 
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