Multiwire circuit for refrigerator & laundry.

[Nitel]

I've looked and maybe I missed it, but are there restrictions using 20A multiwire circuit for the refrigerator and laundry circuits?

Older ('40s) home. Already replaced TL screw type fuse panel with breaker style. Home has kitchen, laundry, bedroom, living room and back addition on the same 30A circuit. Need to move the frig and washer/dryer to separate circuits.

Think I can use multiwire for this, but perhaps with the inductive loads it's not permitted.

I'll look again in the NEC.

Thanks,

 

[Ponchik]

You are fine as long as you have a common disconnect on your breaker, of course if you are under 2008 or 2011 NEC.

 

[Nitel]

I know about the dual breaker and identifying the multiwire conductors with a zip-tie if they are not the only wires in the raceway. I wasn't sure inductive loads qualified for these circuit types. I know multiwire circuits are not recommended for office recepticles where electronic equipment (copiers, computers, fax, servers etc), are used due to the possible harmonics.

Thanks. Up late like me.

 

[tom baker]

No restricton on type of load. MWBC are often not used for computers due to high harmonics causing overheating of the neutral. This is a design issue.

 

[kwired]

No restricton on type of load. MWBC are often not used for computers due to high harmonics causing overheating of the neutral. This is a design issue.

There is a difference in having MWBC's in a data center or other IT area with several computers compared to a single desktop or notebook computer in a dwelling that may happen to be plugged into a MWBC, even it it has a few additional peripheral devices associated with it.

Of course the introduction of AFCI's has limited installing MWBC's in new construction of dwellings.