Conductor Taps

[kevin458]

Which section of NEC deals with the taps of conductors from bus-bar; is it allowed that for short length, a cable is run from a panel to a load without a breaker in the panel. Thanks

 

[Canton]

Which section of NEC deals with the taps of conductors from bus-bar; is it allowed that for short length, a cable is run from a panel to a load without a breaker in the panel. Thanks

Would it be a tap if it does not leave the enclosure? If it does then it will need an ocpd where the tap terminates 240.21***

 

[electrofelon]

Which section of NEC deals with the taps of conductors from bus-bar; is it allowed that for short length, a cable is run from a panel to a load without a breaker in the panel. Thanks

What kind of bus bar is it?

 

[kevin458]

MCC Bus

 

[electrofelon]

MCC Bus

I do not have much experience with MCC's but as far as I now what you propose would be no different that tapping the bus bar of a panelboard, bussed gutter, or busway. Look at the definition of "feeder" and the tap rules in 240.21. Also you may want to consider 110.3(B). A picky inspector could require approved lugs from the manufacturer and possibly even their overall approval.

 

[augie47]

I do not have much experience with MCC's but as far as I now what you propose would be no different that tapping the bus bar of a panelboard, bussed gutter, or busway. Look at the definition of "feeder" and the tap rules in 240.21. Also you may want to consider 110.3(B). A picky inspector could require approved lugs from the manufacturer and possibly even their overall approval.

I agree. Tapping the buss on any factory assembly is frowned upon by most inspectors (altering listed equipment) unless authorized by the manufacturer.
In any event, taps would be covered by 240.21

 

[kevin458]

If the tap conductor runs from the MCC to a load which has its own main breaker, then the conductor will still be protected by the breaker; the only difference would be that the breaker would be located inside the load-cabinet instead of inside the MCC. Is this arrangement allowed by NEC 240.21(2)(2)?

 

[petersonra]

I agree. Tapping the buss on any factory assembly is frowned upon by most inspectors (altering listed equipment) unless authorized by the manufacturer.
In any event, taps would be covered by 240.21

You can't just drill some holes in the MCC bus and attach your own lugs but there are ways every manufacturer has to tap an MCC bus. The easiest way is to add a feeder switch or breaker to an empty section.

There are other solutions, but they vary between manufacturers.

 

[electrofelon]

If the tap conductor runs from the MCC to a load which has its own main breaker, then the conductor will still be protected by the breaker; the only difference would be that the breaker would be located inside the load-cabinet instead of inside the MCC. Is this arrangement allowed by NEC 240.21(2)(2)?

That is a common tap rule setup. Note that you have to meet ALL the requirements in 240.21(2). Also for completeness and clarity, note that the breaker the tap is feeding, is not providing complete protection for the tap conductor. It is only protecting it from overload and provides no short circuit protection. This is why the tap rules are restrictive.