multi-wire branch neutral

[iwire]

Really? The breaker will open, even with the handle locked in the closed position? Guess I should bust one open and look for the clutch.

Yes a breaker will trip even if a drunken cousin has crazy glued the handle in the 'ON' position.

Anyone know if there is a device that can be attached to a breaker (1, 2, or 3 pole), with the ability to "dial in" load? The purpose would be to test the reliability of the breaker.

Yes they are available.

They are large, expensive and take specific training to get meaningful results.

One more thing. Not sure of where to find it, but an experienced electrician told me that the holding time of breaker is relevant to the load. I.E. 20 amp breaker will hold 20 amp load for 1 hour, 18 amp load for 3.

Yes it it is true of breakers and fuses.

Your numbers are off and change from breaker to breaker.

You can get the breaker trip curve charts from the breaker makers.

A 20 amp breaker should be capable of sustaining 20 amps for 3 hours minimum.

The same 20 amp breaker could hold 25 amps forever and still be perfectly fine.

A 30 amp load on a 20 amp breaker may take a few minutes to trip.

The breakers we use on a daily basis are not all that complicated or accurate.

 

[don_resqcapt19]

Mike,

One more thing. Not sure of where to find it, but an experienced electrician told me that the holding time of breaker is relevent to the load. I.E. 20 amp breaker will hold 20 amp load for 1 hour, 18 amp load for 3.

The UL standard permits breakers and fuses to hold 135% of their rating forever without tripping.
Don

 

[celtic]

Re: multi-wire branch neutral

See 210.4. You will not need a three pole breaker or handle ties unless all three ungrounded conductors land on one yoke or piece of equipment.

Roger

Roger...let me divert your attention over here ~>MWBCs....tell me again ?'s

Your statement "...or piece of equipment.", has got me confused. :?

(I'd like to keep my ?'s and issues seperate from the OPs...thanks)