Is it safe to replace a NEMA-50R oven cord with a NEMA-60R?

Question

Trying to be as succinct as possible:

1. I ordered an induction oven that is rated for 50A and NEMA-50R according to the manual.
2. I called an electrician and he recommended we install 60A breaker and NEMA-60R receptacle because the oven is pulling nearly 12kW (his logic)
3. Therefore he wants to change the cord the oven comes with from 50R to 60R NEMA.

Is this dangerous? They've already done the following:

1. Installed the breaker (60A)
2. Installed the wire in the wall (6 guage fit for 60A)
3. Installed the outlet (NEMA-60R)

The oven arrives tomorrow and the electrician is coming to do this last step of changing the cord. But I am having second thoughts (as a non expert non electrician) as my appliance delivery guys were very confused by it.

I've already spent the money and the installation is 90% done so there's no coming back financially, so at this point I need to make a choice. At this point I could tell the electrician to come back, swap out the outlet to NEMA-50R, swap the breaker from 60A to 50A, and not mess with the oven cord. Or I could go with their plan and let them change the oven cord.

My priority is safety at this point. Let me know.

Answer 1

It seems pretty clear that this is designed for a 50A circuit. There are some special rules regarding ovens, and the manufacturer probably did their best to make this work on a 50A circuit because that is a typical size.

Of course, they probably end up causing some other problems with replacements of older ovens because 40A and 50A circuits use the exact same receptacles, and plenty of people have 40A circuits with 40A/50A receptacles. Those people may blindly plug in their new 50A oven to a circuit that is rated (wire size and breaker size) for 40A and either end up with nuisance breaker trips or more serious problems like fires.

But you have the opposite problem - the electrician wants to oversize things. That is OK for the wire, but not for the breaker. The installation manual clearly says everything needs to be either 40A or 50A, depending on the particular model. Installing a 50A-rated appliance on a 60A circuit risks the small but real possibility of a problem with the oven resulting in an overcurrent situation that is not stopped in time, resulting in damage to the oven. Not likely - there are general multiple levels of protection in oven design - but still possible.

If the electrician insists, contact the manufacturer and get an answer form them. If they say 60A is OK, let the electrician do this. Otherwise, replace the breaker with a 50A breaker and stick with a standard 50A cord/plug.

It also looks to me like this oven can be hardwired, but it is not 100% clear from the manual excerpt. If it can be hardwired then I would:

• Hardwire with an appropriate cable. Typically that is a "wire whip" rated for 50A, though if rated for 60A that will do no harm.
• Replace the 60A breaker with a 50A breaker.

That will eliminate a common point of failure with high-current devices - the receptacle. Then you can also tell the electrician: If I get nuisance trips then you can come back and install the 60A breaker, but I'd rather stick with 50A for now. No harm will come from using a 50A breaker on 60A-sized wire. Your electrician is correct that if you use a 60A breaker then you need to use a 60A receptacle and plug/cord, but if you eliminate the receptacle and plug and replace the cord with an appropriate cable then you solve that problem.