Wafer breaker with multiwire circuit

Multiwire circuit on a wafer (twin) breaker. Neutral showed no sign of overheating. Your thoughts? :slight_smile:

same leaf.JPG

If that double pole breaker serves a 14-3 or 12-3 wire and is supplied from the same buss, it may be a problem at the neutral at some future time when higher loads are imposed on it. Not correct!

With that arrangement, the load on the neutral is additive of the loads from the hots (eg. #14 AWG…9 amps on each hot = 18 amps at neutral). When each breaker is served from a different buss, the load on the neutral is the difference of the two (9 and 11 amps on hots = 2 amps on neutral).

The photo is inconclusive. Do you know that both of those conductors on that CB, the red and black, are from the same cable?

Brian Thanks - that’s what I was thinking.

Robert - Yes - I traced them back to the cable where it entered the panel. The neutral showed no signs of overheating, but I guess it is likely to in the future.

Thanks for your replies guys!

It’s wrong but you will not see any overheating since the multiwire circuits are typically low current such as disposal/dishwasher or gas furnace airhandler/attic lights etc.

14-3 is used for kitchen countertop split receptacles here; a neutral on one of these circuits could easily be overloaded if hots are fed from the same buss and a couple of heavier drawing small appliances are being used!!

Good info - Thanks Bruce.

#14 AWG conductors would not be permitted on a SABC servicing counter receptacles since that circuit would be required to be 20 amps.

20 amps according to current codes, but this house was built in the 60’s.

What does this stand for?

Small Appliance Branch Circuit

Ahh, that makes more sense. :cool:

Does the NEC not allow 15A, (3 wire) split countertop receptacles or is it all 20A circuits to the kitchen. Here there can be a mix depending on proximity to the sink (need 20A GFCI protected receptacles within 5’)

All receptacles serving kitchen counter tops require GFCI protection regardless of their proximity to a sink. They also are required to be on 20 amp circuits when serving the counter top.

So from what I read… no more 15A, 3-wire split receptacles along countertops there now?

Correct. The requirement for 20 amp circuits in that location has been around for a long time. :smiley:

We added the option of the 20 amp circuit in 2001; in 2006, the 5’ GFCI rule for proximity to the sink(s) was added.

What 5’ GFCI rule? Is that in the NEC?

No, it’s Canadian. Ours is the CEC…Canadian Electrical Code.

Brian, could you add your location to your profile?