50 amp circuit with smaller receptacle?

Looking at the spec sheet for my oven it says tat 3.7 KW rating at 240v only requires only 20 amp circuit min protection. Can I use a just 30amp receptacle. My feeling is yes. Just like putting 15 amp receptacle on a 20 amp circuit.

Thanks

 

Sorry, but your feeling is wrong. Here are the rules:

• A 15-amp circuit may contain 15-amp receptacles or less.
• A 20-amp circuit may contain 15-amp or 20-amp receptacles.
• A 30-amp circuit may only contain 30-amp receptacles.
• A 40-amp circuit may contain 40-amp or 50-amp receptacles.
• A 50-amp circuit may contain only 50-amp receptacles.

 

Well that leaves me two options then...use the 50amp receptacle or replace the breaker with a 30amp double pole CB and use a 30amp receptacle. Is this acceptable?

 

The installation instructions for many cooking appliances specify a breaker size. Please consult your instructions. If they call for a specific breaker, then you must use exactly that breaker, no more and no less.

 

the spec sheet does not state exactly what CB to use. It specifies this...

0-4.8 Kw 20amp min
4.9-6.9kw 30amp min etc.


and the serial plate on the oven states it is a 3.7kw so I am assuming that this means I need a 20amp 240v double pole breaker. If so do they make such a receptacle to match up with this combo? I have found plenty of 30a and 50a range recept's. Plus I know one of the prongs is going to supply 125v for the electronics. I have 6 gauge wire running from the panel, but i know bigger is ok, but smaller gauge is not allowed.

Thanks

 

Gnftr42; you mention connecting a receptacle rated at 30 amps in a circuit rated at 20 amps and conclude---"just like a 15 amp receptacle on a 20 amp circuit"----Your conclusion is wrong because the rating of the 15 amp receptacle is LESS than the rating of the 20 amp branch-circuit whereas the 30 amp receptacle EXCEEDS the rating of the 20 amp BC.

Table 210.14 lists the MIMIMUM rating of receptacles on BC's of various ratings and applies for circuits with 2 or more receptacles. (Art. 210.24). Art. 210.21 (B) (1) Single receptacle on an Individual Branch-Circuit, reads---"A single receptacle on an individual Branch-Circuit shall have a rating NOT LESS than that of the Branch-Circuit. I construe that this wording (not less) implies that using a receptacle with a rating that exceeds the BC rating is permmisable.

Often it's what the Code DOESN'T state that must be considered such as ----" On an indivudual BC with a single receptacle the rating of a receptacle shall not exceed the rating of the BC" Code does't state this.

 

Thanks John and Pat,
Consulting the code a little closer I also ran into the problem of putting a plug with 4 wires into a receptacle with only 3. So correct me if I am wrong but I have to hard wire this configuration using split bolts in a box, binding the gound and the neutral under the same bolt. I am going with the 30amp breaker and staying with the 6 gauge wire since i can't derate in the same BC. Anyone see any problems with this solution?

 

If you have a plug with four wires and four prongs, and a receptacle with three holes and three wires, you have to change the cord and plug (and the connection to the appliance), not the receptacle.

 

Currently I do not have any plugs or receptacles or plugs. This is remodel construction. The only thing I have in place is 6-2 running from the panel and 4 wire pigtail in flex from the appliance. My understanding is the only way to legally connect them is hard wired in a 4in box. Skipping plugs and recepts.

Thanks

 

If you have 4 conductors on the appliance lead to connect it may be 2 Un-grounded conductors,Red & Black, a Grounded (Neutral) conductor, White, and a bare or Green Equiptment Grounding Conductor (EGC).

You state that you have a # 6/2 Branch-Circuit cable which could be 2 insulated current conductors as the 2 Un-grounded conductors and an EGC. You may not have a cable conductor for the Neutral connection.

 

yep exactly Pat, Appliance has a Black and a Red, a neutral and a bare copper EGC. The Branch circuit has black and black with red stripe, each supply 120v with a bare ECG. I hooked up one black from the BC to the black, and the other to the red with split bolts and taped them up. Then I tied the neutral, the bare ECG and the Branch bare wire with new grounding wire for the box under another split bolt and put then all in a 4 in box. I will get the inspector to look at my work before I tie it in to the new 30 amp breaker.

 

If this is new construction (ie. remodel ), your inspector will probably require a new 4 wire circuit for the oven.