What's this component called?

**Marc M** · 06-09-2011, 09:09 PM

Just wondering what is the name of this component. It's attached to the main disconnect and serves a remote panel elsewhere, which does not possess a disconnect.

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Roger Frazee · 06-09-2011, 10:09 PM

Mark

That is a sub-feed lug. It simply provides a means to tap the two busses of the panel it is installed in. It is not an overcurrent device. About the same thing as feed thru lugs only a more resourceful means of doing so.

**Marc M** · 06-09-2011, 10:12 PM

Originally Posted by Roger Frazee

Mark

That is a sub-feed lug. It simply provides a means to tap the two busses of the panel it is installed in. It is not an overcurrent device. About the same thing as feed thru lugs only a more resourceful means of doing so.

Hey Roger,
thanks for the information, much appreciated.

Henry Zawacki / K and H · 06-10-2011, 06:40 AM

Agreed Sub-Lug

**Michael Thomas** · 06-10-2011, 06:52 AM

First time I saw one of those, I turned up this:

Sub-Feed Lug Block

**Tom Rees** · 06-10-2011, 06:53 AM

Roger, I don't understand why this has no overcurrent protection? Could you help me out.

Michael Gantt · 06-10-2011, 06:59 AM

More important in my mind, is why would you want to feed a subpanel without having a means of shutting off the circuit from this panel to the sub panel? Is this just the epitome of cheap, or is there a reason you'd find switching capability not worthwhile?

**Joe Klampfer** · 06-10-2011, 09:16 AM

Jerry, I'm surprised! No submarine argument ?

**Tom Rees** · 06-10-2011, 10:05 AM

Thanks Michael, That was a good link.

**Jerry Peck** · 06-10-2011, 06:03 PM

Originally Posted by Michael Gantt

More important in my mind, is why would you want to feed a subpanel without having a means of shutting off the circuit from this panel to the sub panel? Is this just the epitome of cheap, or is there a reason you'd find switching capability not worthwhile?

Originally Posted by Joe Klampfer

Jerry, I'm surprised! No submarine argument ?

Joe,

Just got back here ... I was out in my submarine checking my subpanels ...

I can see various problems with those sub-feed lugs, namely that there is no overcurrent to the feeders, but ... those feeder conductors may meet one of the tap rules which allows the overcurrent protection to be at the load end of the feeders ... then again, those feeders may not meet those requirements ... not enough information present to know.

**paul hardy** · 06-10-2011, 06:28 PM

Jerry,
Just a question the main appears to be next to that device would that protect the buss and the conductors to the secondary panel?

**Jerry Peck** · 06-10-2011, 06:37 PM

Originally Posted by paul hardy

Jerry,
Just a question the main appears to be next to that device would that protect the buss and the conductors to the secondary panel?

Paul,

*IF* the feeder conductors were of sufficient size for the main disconnect to serve as the overcurrent protection for their rating, but the service entrance conductors are of a much larger size, and I can't read the breaker size (200 amps?). Feeder conductors (not using the tap rules) are typically larger than service entrance conductors for a given amp rating because feeder conductors are not allowed to use the same table as service entrance in one-and two-family dwellings.

The bigger thing in that photo, though, is that is one of the Zinsco panels and it is a good possibility that the breakers have welded themselves on to the bus bars. Zinsco panels are not quite as bad as FPE ... but not enough 'not quite as bad' to argue the finer points - recommend replacing that panel because it is a Zinsco. At least 'ON' is "up" in that horizontally oriented panel interior.

**paul hardy** · 06-10-2011, 06:49 PM

That is what I was thinking, based on the frame size of that main I believe it could only be maximum 125 amp simular to this 100 amp here but I agree it is zinsco and should be replaced anyway.

Zinsco Molded Case Circuit Breakers

Roger Frazee · 06-10-2011, 07:07 PM

Originally Posted by Tom Rees

Roger, I don't understand why this has no overcurrent protection? Could you help me out.

Tom

First look what Jerry had to say in post ten

I can see various problems with those sub-feed lugs, namely that there is no overcurrent to the feeders, but ... those feeder conductors may meet one of the tap rules which allows the overcurrent protection to be at the load end of the feeders ... then again, those feeders may not meet those requirements ... not enough information present to know.

I would have to agree with what Jerry is saying here. Sub-Feed lugs are almost always used under one of the tap rules. Most common in my experience is the outside unlimited tap rule. Some of the tap rules allow overcurrent protection at the end of the feeder instead of at the supply. We would have to know ... location of the service equipment (inside or outside) ... size of the service disconnect and awg size of the feeder and more information about the remote panel and its location.
I beleive it was mentioned by Marc that there is no single disconnect at the remote panel which would imply it is using the 6 disconnect rule or it is just mlo depending on the panels location. More info is needed.

In many panels you have to be very careful with the feeder bending space when using these sub-feed lugs.