Sub-panel tapped to feed another sub panel

[GerryC]

Hay Guys I have another question regarding a Sub-panel in a Co-Op Unit. The main service equipment is in the basement with a separate main C/B to my Unit. The Main lugs on the Unit sub-panel are used to feed another sub panel (laundry unit 30 amp 2-pole). In a larger panel I would put a C/B to the next Sub-panel but this panel only holds 3 Tandem C/B 6 circuits which is ok. If my thinking is correct even if the feed to the Unit sub-panel is the same size as the feed to the laundry sub-panel (the one tapped off the main lugs) this illegal, can any one confirm my suspicion.

 

[petersonra]

It might well be legal if the laundry sub panel has a main circuit breaker. However, normally these would not be tapped off of a unit sub panel but the house sub panel because the laundry is a shared facility and should be paid for by the landlord and not any individual unit.

 

[Coppersmith]

So your unit MLO subpanel is being fed from a main breaker in the basement and you want to tap the feeder inside your subpanel and run it to feed another subpanel? Did I restate that correctly? I believe that would be compliant since the feeder to your subpanel is protected by an OCPD. It doesn't matter that the two subpanels are the same size. In fact, either panel could be bigger. The OCPD protecting the feeder will trip if too much current is drawn.

 

[GerryC]

Coppersmith - When they tapped the sub-panel now we have two wires under the same lug not a lug on top and bottom of each phase leg. So what you are saying either way this is legal but you must have the same size conductors feeding both sub panels correct. One other question what is
OCPD, are you referring to the Main breaker that feeds the Original sub-panel?

 

[GerryC]

petersonra - The Laundry sub-Panel has one 2-pole 30 amp C/B to the Laundry unit ( combo washer and dryer) and is tapped off the Unit sub -panel not the Main panel in basement (co-op service equipment). In this case as a co-op share holder we pay our own electric, the laundry unit is in my apartment unit.

 

[Coppersmith]

OCPD = Overcurrent protective device, a circuit breaker, a fuse, or another device that measures the current and opens the circuit at the set amperage.

Two wires under one lug is not allowed unless the lug is listed for such use. You can use an insulation piercing connector to tap the feeder.

 

[GerryC]

So what you are sayingi that the Lug in the sub-panel has to be rated for two conductors under one lug by underwriters and manufacture. So I need to know name of panel ( I think GE) and how old (1970's I think) not sure have to take another look. Thanks for the info.

 

[Coppersmith]

So what you are sayingi that the Lug in the sub-panel has to be rated for two conductors under one lug by underwriters and manufacture. So I need to know name of panel ( I think GE) and how old (1970's I think) not sure have to take another look. Thanks for the info.

It likely isn't. Consider using insulation piercing connectors for the tap.