"interlocked back-feed circuit breaker"

[LowGear]

I was up reading a thread in the "Society's" section and ran into the above phrase.  As I'm not a member I couldn't ask there so I came over here.  This suggests there is a mechanical connection between the main breaker on a panel and one of it's circuit breakers.  And to this I say "Huh?"!  And ask what do they look like and where would I shop for one?

Casey

[rcavictim]

I've seen one of those in a picture.  It is a flat metal bracket that slided towards and away from the Mains Breaker handle and also creates interference to the end location outlet circuit breaker slot nearest the Mains Breaker when the Mains Breaker is ON or closed.  The Genset Branch Circuit would go in this blocked location.  Only way it could be turned on to feed the panel (and the house through the panel) would be with the Mains Breaker in the OFF position which allows the sliding metal tab to clear the Genset Branch circuit breaker handle. With the Genset breaker paddle ON the sliding strip is blocked from slideing and thus prevents the Mains Breaker from being turned back on.  Clever idea!

[rcavictim]

Clever idea!

Clever idea but holy cow, $100 for a small piece of stamped aluminum that costs maybe 5 cents to produce .....
BTW, these interlocks are specific to the breaker system being used and not all systems are covered (I tried to get an interlock for my breaker box with no luck)

If I were to use such a scheme I'd just fabricate my own sliding strip out of 14 GA mild steel.  All you need is a drill, a vice, small round file and a hacksaw or power tools if you have 'em.  It's called DIY. 

[LowGear]

I think I see said the guy with the small dark glasses.

Thanks,

Casey

[rcavictim]

If I were to use such a scheme I'd just fabricate my own sliding strip out of 14 GA mild steel.  All you need is a drill, a vice, small round file and a hacksaw or power tools if you have 'em.  It's called DIY. 

That is entirely possible as long as you realize it is about as illegal as running your system without any kind of transfer switch and your method of operation is to backfeed a circuit after pulling the main breaker.

Jens,

This in fact IS a Mechanically Interlocked Transfer Switch.  That said, the quality of the components is something to consider.  I myself would not choose to trust my life to a circuit breaker marketed for the home market.  Some of these have been shown to have issues.  When I saw the picture of the device I mentioned I was actually surprised that such a thing would be code approved.

[LowGear]

I'd hate to have to explain to the fire insurance adjuster what that nifty thing in the remains of the breaker box was for and where it came from.

But you are saying that manufactures have approved models?

Casey

[Carlb]

Casey,


They do have manufacturer approved models to fit various load centers.  I elected to install a separate manual transfer switch with 16 circuits. My local electrical inspector had no problem with the installed transfer switch / load center and approved the installation. 

In the picture you will see the main load center on the left and the manual transfer switch on the right.

Carl   

[Ronmar]

You can also buy loadcenters/main panels already preconfigured with the sliding plate interlocked backfeed breaker for generator power.  I see them all the time in electrical supply stores and the box store electrical department.  A simple safe practical concept that is becomming more and more mainstream...