[iclubb]

A while back I posted that my duel fuel oven wasn't working -- at least the electrical heating element in the oven wasn't heating. A repairman came by just to confirm what I already knew, which is that the oven was not receiving 240 volts -- 110 on each hot wire but nothing when joining them. We recently did a renovation (we just moved into the house) and replaced the 40 amp sub panel located in the kitchen with a 60 amp. A new GFCI was run to the upstairs bathroom but otherwise the wiring was left as is.

The contractor and electrician who did the panel work came by yesterday and said that the wiring to the kitchen was totally wrong. Basically, everything is 12/3 wires. The oven is rated to need a power source of 40 or 50 amps, with a 4 prong 240 volt outlet. Also, the appliances don't have their own circuits... the refrigerator, microwave and a couple of 15amp outlets are on the same circuits, leading to the switches flipping when microwaving and using the toaster oven, say. The oven and the dishwasher are on the same circuit. Also the two outlets near the sink are not GFCI, which I realize is wrong. They say this is all not to code and claimed the oven should never have worked with those wires, even though the previous owner swears up and down that it worked great until the day they left.

Now, the reason that the oven didn't work even though he thought he had done the wiring the same, was that he didn't realize they were supposed to be joined together since there hadn't been a 220 breaker in the old panel box. When he was here yesterday he wired it so that the oven outlet did put out double voltage (although it could only manage 216 actually), and lo and behold the heating element got hot. My questions are: how imperative is rewiring this setup? The previous owners lived for 6 years with this setup working well & without a problem, so they say, and as you can see below I trust them. Is the oven safe to use in this configuration?

I'm also concerned about being hoodwinked by contractor/electrician currently. What shenanigans, if any, could they be up to? Should I be mad that this was not dealt with or brought up when they did the original panel work?


For what it's worth here's my original post:

The background: recently purchased house with a duel-fuel (gas range, electric oven) stove. Did some renovation work including brand new main (100amp) and secondary (60amp) electrical panels. Electric oven has not worked since we moved in (ie after reno work). Previous owners swear that it worked until the day they moved out and I trust them implicitly, 100%. They actually moved up the street and I see them every day, and I've come to know them, and so I really believe them. So..

Repair guy was here and measured voltage coming out of socket in the wall that oven is plugged into. (It's a jenn-air by the way.) He was able to get 110 on either side, but no reading whatsoever when spanning the two trying to get a 240v reading. Is it possible that the problem is at the circuit panel? Is that where an outlet is made to be 240? Given that that's what's changed since oven stopped working, that's what my money's on, but as is probably obvious, I know next to nothing about electrical stuff. Thanks in advance.

[donf]

Wait a minute, was a permit pulled for the renovation? Usually if there is 60% room renovation work being done, the electric wiring must be brought up to current code level. Also an Electrical Inspector has to approve the final work. Was an Electrical Inspection done?

The NEC has specific requirements for kitchen wiring.

There has to be a minimum of two 20 amp circuits for the kitchen counter outlets.

In a residence, the range needs to be on a independent 120/240 volt 40 or 50 Amp Branch (See NEC Chapter 2, Article 210.23 (C))

A range requires a four wire (Hot - Hot - Neutral - Ground configured cable) 8/4 AWG, at 75C cable. That is protected by a dual pole breaker that is joined at the handles. You cannot use the sub-panel feeder as circuit protection for this circuit.

There is no excuse for a licensed electrician to "Not Know" a properly configured Range Branch Circuit, Period!

[iclubb]

We actually didn't touch the kitchen in the reno. Basically the electrician didn't know that the oven was an electric one because it has a gas top (it's "dual fuel"), and he just replaced the panel with all the wiring left as is, and as I said there wasn't already a dual pole breaker for the oven. He says the kitchen as we found it would fail an electrical inspection. In any case it is clear from your response that our wiring is insufficient code-wise for this purpose.

You cannot use the sub-panel feeder as circuit protection for this circuit.

This means that the wire needs to be run from the main panel downstairs, or just that it needs a dual pole breaker at the sub panel?

[donf]

It means that you sub-panel feeder can only feed the sub-panel.

In the sub-panel, you would need a 40 or 50 amp dual-pole breaker to protect the circuit from the sub panel to the appliance.