Replacement Range Circuit Rating

[iggy2]

Multi-family development (70 units) is looking to replace their old 20" wide electric ranges with new. The existing circuits are 50A 2 pole circuit breaker and a 50A 4 wire receptacle (we assume wire is correct at 50A...). Many 20" electric ranges call for a circuit having a rating of 40A. Can a 40 amp range go on the 50A circuit per 422.11(E), Single Non-motor Appliance: ...OCP shall comply with the following: (3) Not exceed 150 percent of the appliance rated current if the overcurrent protection rating is not marked and the appliance is rated over 13.3 amperes."

Many of the manuals on-line say a 40 amp circuit, so the above may not apply in that case, since that could be interpreted to be the "overcurrent protection rating". But if the manual just says - "draws 37 amps" (for example), then 37 x 150% = 55.5 ampere circuit. So the existing 50A circuit could be used.

Agreed???

 

[JFletcher]

If the mfg specs a 40A OCP, then just swap the existing 50A breaker for a 40A. If they spec 'must be at least 40A', then you would be gtg with the 50. The receptacles will be the same anyway; afaik, 4 prong 40A receptacles do not exist, so the ovens will have a cord that goes into a NEMA 14-50R receptacle, or be hardwired.

 

[Cavie]

Check on that 4 wire circuitry. 4 wire was not common in older 20" range wiring methods.