So I have an old main panel I don't want to touch - yet? Customer is cash poor with baby due... But will be changed in near future.

Anyway, would you call this a tap?

All conductors are #2 cu THWN/THHN for the service and feeder conductors- 100A main in backfed old style CH breaker, with 3 other 20A circuits, and a 60' feeder off the lugs to another (new) sub on (E) feeder.

420.2 describes a tap as such:


italics mine....

If the service conductors are 100A, so is the panel MCOP, and the feeder is rated for >100A, not <, how would this be a "TAP"?

Inpector wants an OCPD for the feeder alone. Calling into play the TAP rules.... If the feeder conductors were rated for 80A, I could see that....

What say you?

Connections to the line side of the service disconnect are not taps, they are still service conductors. All service conductor rules still apply

This is on the load side of the back-fed Main... The OCP for the feeder is the Main.

240.21 explains taps and i dont see where you can have this tap 60' feet long unless its outside or in a high bay building. 240.21(B)(1) is not over 10' and 240.21.(B)2 is not over 25'. if im reading your post correctly the length of your tap is no good.

It is not a tap.

A tap to the NEC is a conductor that has an overcurrent device ahead of it larger than the conductors rating.


In this case all the conductors are rated over 100 amps and the over current protection is 100 amps.

All is safe and it is not a tap.

yes the #2's are good for 100 amp. 240.21 requires ocpd in each ungrounded circuit conductor and it shall be located at the point where the conductors receive their supply except as specified in 240.21(A)-(G) which are the tap rules. so where is the ocpd for this feeder. the service main which is 100 amp is the service disconnect and ocpd and the ocpd for this feeder? if its not a tap then it needs a ocpd, not the service main disconnect and ocpd.

Yes, the 100 amp service disconnect / breaker is in fact a legal way of protecting the conductors.

Bob- If we assumeing copper conductors I agree but if these are aluminum feeder conductors, we have to protect them at 90a.

George Happy T-Day.

I agree with you, it happens that the Mark mentioned it was #2 cu THWN/THHN.

Bob

Same to you Bob and your family. And thanks, I missed the "cu" - got to get those glasses cleaned.

so you say its a code install. if a sparky has to work in the sub and wants to shut it down you have to throw the main? not a good install. for a $20 breaker is it not better to have a 2 pole breaker on the feeder to the sub? i still dont think this satisfies 240.21 as each ungrounded conductor requires an ocpd at the point it gets its supply. the main is a ocpd for the entire panel and acting as the service main not a feeder ocpd

Morning Danny.


Yes


I agree


I agree.

But this is an NEC forum and I am going to give an NEC answer to the best of my ability.


The overcurrent protection for the feeder is at it's point of supply, no part of the 2 AWG conductor is ahead of the circuit breaker.


There is no NEC restriction preventing us from using that breaker for both.

Current is current, the service main is as capable of protecting the feeder as the panel.

Sounds backwards but, I would pass it.
Remember to label the "Main" as the Service Disconnect.
Alan--

The choice of not adding a breaker for the feeder is mitigated by this:

• The current panel is an early 60's CH with 120 on one side, 120 on the other - there are only two 240 slots int he panel
• the current breaker is a 4-position 100 "beige" CH taking up both 240 slots - the clips on the other side of the breaker act as the hold-down for this back-fed breaker feeding the panel.
• Using a smaller 100 breaker for two slots would offer no hold-down for the main.
• Changing this units main panel would trigger the changing of the whole service for the multi-unit building. (Something they want to do anyway, but not yet.)
• The building is still a TIC, but will need some heavy work during condo conversion soon - to include this and the rest of the units and house metering.

Either way the Inspector is working from opinion rather than code IMO, and on my customers behalf, I get the fight for it....

Vote me with Bob, this is a legal feeder with a splice and the tap rules are not applied because the conductor is protected at it's ampacity.