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George Krause
12-18-2009, 04:24 PM
In Michigan, it is common to see a metal brace at the dishwasher/disposer breaker at the electric panel that prevents the breaker from tripping. While observing this, I have attempted to manually turn off the breaker, but it cannot be done with the metal brace in place. This seems to be unsafe to me, but it is commonly seen at newer panels, and has evidently passed municipal code inspectors. Any explanations from the electrical whizzes out there?

Gunnar Alquist
12-18-2009, 04:35 PM
In Michigan, it is common to see a metal brace at the dishwasher/disposer breaker at the electric panel that prevents the breaker from tripping. While observing this, I have attempted to manually turn off the breaker, but it cannot be done with the metal brace in place. This seems to be unsafe to me, but it is commonly seen at newer panels, and has evidently passed municipal code inspectors. Any explanations from the electrical whizzes out there?

George,

Are you sure it actually prevents the breaker from tripping? Typically, these "lock-out" devices will prevent a breaker from being turned off or on, but will still allow the breaker to trip. Tripping happens internally and the handle movement/placement is primarily to signal which breaker tripped.

George Krause
12-18-2009, 04:40 PM
I did not short the breaker, but I could not switch the breaker manually. So it may actually trip internally, eh? Just what is the purpose of the brace again? And why is it almost always on the dishwasher/disposer breaker?

George

Tim Spanos
12-18-2009, 04:42 PM
I was curious to why it is common in michigan to install this metal bar on the dishwasher/disposal breaker....i have heard of them for exit sign and emergency lighting or burglar or fire alarm branch circuits but never dishwasher......just wondering

Jim Luttrall
12-18-2009, 04:57 PM
Most modern breakers will trip internally even if the handle is blocked.
I think Gunnar is on the right track, this would likely be a lockout device designed to keep the circuit from being energized when locked in the off position to take the place of a disconnect switch withing sight of the unit.

Bob Spermo
12-18-2009, 05:10 PM
Tim,

The breaker you speak of for the dishwasher/disposal is probably wired to a receptacle (dual plug) that serves both appliances. Many times they share the neutral but the copper strip between the hot screws has been removed. Thus you have two "separate" receptacles that share the neutral. The strip that combines the circuit breakers cuts power to both sides of the receptacle for worker safety.

Bruce Ramsey
12-19-2009, 03:29 PM
Lock out Tag Out is a common safety protocol in industry. The breaker is physcially locked in position so that no one can come along and operate the breaker. This is usually done during maintenance so that the repair person does not get accidently shocked.

The metal strip is so you can place a padlock on the breaker.

Jerry Peck
12-19-2009, 04:38 PM
The breaker you speak of for the dishwasher/disposal is probably wired to a receptacle (dual plug) that serves both appliances. Many times they share the neutral but the copper strip between the hot screws has been removed. Thus you have two "separate" receptacles that share the neutral.


Even with the tab between the terminals left in place, and the receptacle fed with one circuit, that still makes for two "separate" receptacles ... which is why they are referred to as "duplex" receptacles, i.e., there are two - duplex - receptacles on the single strap.

H.G. Watson, Sr.
12-20-2009, 08:52 AM
I suppose that the appliances might be supplied with a MWBC and you're referring to a handle tie used to tie in two single pole breakers which protect the multi-wire branch circuit. This tie causes both breakers to open at the same time should a trip occur one one side of the MWBC the other must open at the same time - otherwise current could "backfeed" on the grounded conductor.

Cap overtop to allow the MWBC to be manually opened then the breakers covered and locked to the open position perhaps.

A photo would be helpful and could resolve the question (of the several possiblities discussed already on this topic thread).

Matt Fellman
12-20-2009, 12:40 PM
I have always assumed these devices are in place for equipment that might need to be serviced but where a box within sight (like A/C compressors) is not practicle. As someone mentioned, it's to prevent the person installing or servicing the equipment from being shocked.

Jerry Peck
12-20-2009, 12:47 PM
within sight (like A/C compressors) is not practicle.


Keep in mind that a lock out at the breaker is not allowed as a substitute for a disconnect as a/c equipment - unless it is part of an industrial process, blah, blah, blah (I doubt that we will be running across that exception as home inspectors :) ). Practical or not, the disconnect is required at the a/c equipment.