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Well I'm doing some wiring in the kitchen before the big remodel in there and I thought I'd install a 40 or 50 amp circuit for an electric range/oven (there's a gas oven currently, but may want to upgrade to electric or even induction one day).

Then it occurred to me.. we only have 100 amp service in the house. Would adding an appliance that uses up to 50% of the max electric load be pushing it? Does this mean I either need to update the service or scrap the idea of an electric oven?

I would like to stay at 100 amp main if possible. The house has a gas furnace, three window electric A/C units on 20 amp breakers (I'm in Kansas, climate is really hot in summer and a pretty cold in winter), an electric dryer on a 30amp breaker, not a lot of lights and stuff as it's less than 1000 sq ft, there's a workshop/garage getting 20 amps IIRC (could be more, especially if I want to weld).

What do you think??

(Bonus question: do I really need #6-4 wire for the oven circuit and how do I connect this to the breaker box?)

edit: thought you guys might like to see the breaker box. (btw, I've already removed the old K&T wiring that you see going to the breaker bellow the main breaker). enter image description here

  • btw, I only "know" that it's 100 amp service because the main breaker is 100 amp. However I haven't sized up the main service wires yet to see if 1 gauge or if it's bigger (I just read that I need to do this) – Dan Mantyla Jan 26 '17 at 21:49
  • If you are removing 2 sets of the baseboard heaters you should have plenty of ampacity. I would go with the 50A and yes large wire then you never have to say why didn't I spend the few extra $ when I put that in to have the 50. – Ed Beal Jan 26 '17 at 22:40
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    For what it's worth, my previous home had an upgraded (modern) 100A service with a 50A range circuit. We never once tripped the main in 17 years, even running power tools, a central air conditioner, and whatever else. – isherwood Jan 26 '17 at 23:20
  • Keep in mind a range rarely draws it's max. The max draw is also less than 50amp, more like 32-38 amps. Rarely do you ever have every heating element on at max. – Tyson Jan 27 '17 at 1:40
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Your panel needs to be reviewed, carefully.

When you do, you'll have no trouble finding 2 spaces.

It's a quality CH panel, albeit with only 20 spaces. I'm not counting the top 2 spaces in each row, which collectively are the main breaker (100A). Good news is, with this panel arrangement, if you shut off the main breaker, everything is cold except those conspicuous large screws. Which makes it more DIY-friendly than most.

I see seven 240V breakers tying up 14 of 20 spaces. That means all 120V loads in the entire house are served by six 120V breakers, which is pretty compact. I don't believe a house can have seven 240V loads. The usual big four are dryer, A/C, water heater and oven. So I suspect many of these breakers are surplus, particularly since they're off.

The only conceivable reason for this many 240V breakers is having all-electric heat, e.g. baseboard, and if that's the case, forget about an electric range/oven - you just don't have enough service.

Two of those 240V loads are 120/240 split phase. The right side middle rows are a 30A breaker, and looks to have the heavier 10 AWG wire, so it looks to be a dryer. The left side 4th and 5th from the bottom is weird because the white wire is being used as a hot, and the red wire is taped white and used as a neutral (which is illegal to do). That's not right. It might be a multi-wire branch circuit or MWBC, serving two 120V circuits, but I doubt it.

I see a red wire that's taped off, that means there's another black-red-white cable with black and white only being used. That seems weirdly sloppy (why use white for a 240V circuit when you have red) which only worries me more about the quality of work in general.

Even worse, look at the bottom right breaker. It's a 60A breaker but that's NOT a 4 AWG wire. It's either 12 AWG or maybe 10 AWG. That needs a 20A or 30A breaker, respectively. I know exactly what those breakers cost, so no excuse! SHUT IT OFF NOW. NEVER turn it back on. Replace with a 20 or 30A breaker respectively, most hardware stores stock CH220 or CH230. And if it trips, it's supposed to.

Other than that, Mrs. Lincoln...

Go through each circuit in the panel, for two reasons. First, to find any more defects -- after all, I could find two whoppers from a photo. Second, to understand what you do have, so you can either trim or consolidate and free up 2 breaker spaces.

Don't bother hunting down double-stuff (duplex/tandem) CH breakers. Yes, they exist, but you really, really need to re-evaluate this panel, given the large number of defects I've seen from one measly photo. And I think as you do so, you'll free up some space.

Oven/range is straightforward

You simply need a 50A breaker and 6 AWG copper (or 4 AWG aluminum). You could go 40A and 8 AWG, but the difference is only a few bucks, and you'll have a wider selection of ovens/ranges if you go 50A. CH 50A breakers are readily available, not quite as widely stocked as the 20/30s but any big-box should have them. You cannot reuse the 60A breaker.

However, cooking on electric kinda sucks, if you're coming from gas. It's a very annoying learning curve, and a lot of compromises and workarounds. Not recommended.

If you must upgrade the panel

CH is a fine system. One option is get a larger CH panel. However, if you replace the panel, you will need to upgrade most of all of your 6-8 120V loads to AFCI or GFCI or both/combo, and that could get costly. The disadvantage to CH or any 3/4" wide breaker is being smaller, there's less space to cram advanced tech, so they're more expensive or unavailable.

Don't go cheap. This panel is much better than the Homelite and other shlock the local big-box is shoveling. (You can't go by brand anymore, as good brands like Square D and Eaton have bought up cheapie sub-brands.) You have to ask for the good stuff. Get a top-shelf panel from a proper electrical supply. And go really big - bare minimum 42-space, 60-space is not too many. If the main breaker for such a panel is too large, bypass it - put a 100A breaker in the normal spaces and backfeed it (much like is occurring in this panel).

  • Thanks @Harper, good info there. You're correct about the 60a breaker, that needs to be fixed. It's going to the only baseboard heater that hasn't been removed yet. All the other baseboard heaters have been removed and thats why the breakers are off. I think the weird circuit with the taped red wire is going to the dryer. I'm not sure what you mean by 120/240 split phase, I'm going to have to do some more reading and research - or find an electrician. Thank you! – Dan Mantyla Jan 27 '17 at 1:54
  • BTW, I love cooking with gas but the decision isn't up do me and the lady likes glass electric stove tops :) – Dan Mantyla Jan 27 '17 at 1:56
  • I have a question: the 30amp breaker with the red wire on the right side of the panel is for the underground wire going to the subpanel in the garage. Does this look ok? Should is be a gfci breaker? thanks! – Dan Mantyla Jan 27 '17 at 15:57
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    The #1 thing to do right now is exchange that 60A breaker with one of the abandoned ones. Garage GFCI, depends if you have a freezer. GFCI in the main panel is nice, it will catch wiring faults in the sub-panel itself, like neutral and ground tied together there. But It's not required in the main panel, normally they're put on individual breaker slots in the subpanel and that is grandfathered. It's nice to have a freezer not on a GFCI. – Harper - Reinstate Monica Jan 27 '17 at 17:45
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    Freezers because an unnoticed GFCI trip can spoil $1000 worth of food. I agree, wire condition is good reason. GFCI's mainly protect humans from shocks (and detect some wiring problems). AFCI's are specifically designed to stop wire problems from starting fires. You can get combo breakers, but not necessarily in CH. – Harper - Reinstate Monica Jan 27 '17 at 22:15
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It's certainly doable, as there are plenty of (older) homes with an electric stove and 100 A service. However, given the electricity demands of modern-day living, you sacrifice in other areas. Those older homes tend to be the ones where you can't run a toaster and microwave at the same time, or a hair dryer and the light in the closet. You could also decide to run a smaller breaker, given that you have gas, and allow for an electric oven only, but not a full electric range.

The bigger problem in your situation is that your electrical panel is full; there are no more spots to put breakers. So if you do want to add a 40 or 50 A breaker for a stove, you need to get a bigger panel at the very least.

You may have service entrance cable rated for more than 100 A, in which case you can upgrade to that level of service with no problem*. If your service entrance is only 100 A, though, upgrading beyond that would entail running new cable from your meter to the transformer - which could mean 100s of feet of thick, expensive cable and possibly trenching.

Yes, you would need #6 wire for the 50 A circuit, and yes you would need 4 conductors (3+ground). When you get a bigger panel it then fits in to the 50 A breaker no problem.


*The main breaker on your panel will be the smallest rating of the following: the rating of your service entrance cable (from the transformer to your meter), your meter, the cables running between your meter and panel, and your panel. So, you could have a 100 A main breaker because the panel is only rated for 100 A, even if everything else in that chain is rated for more (say 125 A). That's the best case scenario, as it just means a new panel, which you'd need anyway. On the other hand, if it's the service entrance cable that's rated for 100 A, but everything else is rated for more, you have a big choice to make.

  • yes the panel is full but many of those double-throw breakers are for old base-board heaters that are getting thrown out – Dan Mantyla Jan 26 '17 at 21:58
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    It may be possible to replace some of the single breakers with tandem breakers if the panel is rated for them. If not your panel is full. Checking to see what the load on the panel is would show if there is enough available ampacity to install a sub panel. Most electricians would suggest to upsize the panel to at least 150A or 200A if you can afford it while doing the upgrades. Most electric ovens do require larger wiring but the derated load value for a 12kw oven is only 33.3amps per table 220.55 Column C (1 appliance not over 12kw the demand is listed as 8kw) – Ed Beal Jan 26 '17 at 22:23
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    @DanMantyla I had a hunch that was the case. Even if you wanted to keep baseboard heating, it could be consolidated onto fewer breakers. – Harper - Reinstate Monica Jan 27 '17 at 1:29
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We (my wife and I) have a 100 amp service. The house was built before 1800, so it's gone through tube and socket to tar coated to (my work) modern wiring. We had an electrician recently change the panel from 100 amp fuses to 150 amp breakers. but the supply is still 100 amp. We run an electric stove (2 x 30 amp), hot water heater (2 x 20 amp), and dishwasher on it in addition to normal electrical lights, freezer, fridge, and outlets. No microwave or dryer! Heat is wood fired boiler and wood stoves. We have yet to have a problem. So it should be doable, but I would strongly suggest an electrician.

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