It's RS647G.  33 years ago would it have used a 40 or 50 amp 240v. circuit and a 14-50R wall receptacle?

It could have used either 40 or 50 amp circuit, if I were installing a single oven electric range I would use 40 amps as it is a lot safer when something goes wrong.

We went a step safer in the warehouse-museum and installed all 25+ ranges and wall ovens on just 30 amp lines.

So Tom I'm surmising you're telling me I'm going to have to have an electrician come out and change the connection the range plugs into.  In ignorance, what's service entrance vs. sub panel.  Is the latter my circuit breaker panel in the garage?

Tom & John, thank you both for responding.   

When we moved into our previous house, there was a mid '80s P7 free-standing range in the kitchen.  When we removed it, we found that it was hard wired with flexible conduit to a junction box.  We'd never seen anything like it, but knowing the previous owner, nothing surprised us.

With very little research, but knowing the type of cord the new 40-amp range required, we bought both the cord and the compatible receptacle and wired it all up.  It was a simple DIY installation, and since the new range was dual fuel, if anything, it required fewer amps than the all-electric range it replaced.   This circuit ran through a breaker box.

So Bob, if you already have 40 or 50 amp service to the range's location, and presumably have seen the type of cord used on similar GEs or Hotpoints, wouldn't this just be a matter of matching up the correct receptacle for that type of cord's configuration (if it's not the same already)?  Getting an electrician involved and dealing with code compliance is just asking for headaches and huge expense.   Even at our current house, when we pulled out my mom's '49 Westy in 2008 and replaced it with the dual fuel Electrolux, I unplugged the Westy from its 1960 receptacle and plugged in the Electrolux.   Done.  It couldn't have been simpler.   Nine years later, no fires, no electrical shocks, and the oven works perfectly.   I don't get why this has to be so complicated.  Maybe I'm missing something.

And yeah, I'd also like clarification on the difference between sub panel and service entrance.  With my limited knowledge, it seems to me that any residential service of 240v would always run through a breaker box, but I don't know if a breaker box is aka a sub panel.  I presume that if no breaker box or sub panel is involved, there would be one of those Frankenstein throw switches for the 240v line at the service entrance.

First off, as long as the current circuit which is in place is safe and adequate for the load, use it.

Arguments can be made for separating the ground and neutral, but let's be honest, here - anything which tears a #8 or #6 cable running straight back to the grounded neutral bus at the service panel is going to knock out everything else with it.

NEC only speaks of 'electrical panel'. Whatever you call it, the 'main' or 'service' panel is the one which is hooked up directly to the power company lines and has no more than six breakers to flip to disconnect everything which comes out of that box from the power company lines.

Everything else may be thought of as a sub-panel.

Only at the 'main' or 'service' panel may the neutral bus be bonded directly to the metal panel box and connected to the ground wire.

Every panel after that may not bond the metal box to the neutral bus and must keep the ground and neutral separate from each other.

Everything else is just a matter of local names and not paying attention to the code.

One interesting note for those looking to update 3-wire to 4-wire - unless local code prohibits it, NEC permits running the ground wire within the same raceway (in other words, indivisible) with the old 3-wire cable. It must be continuous and may not be removable. So many local codes don't allow this that somebody is bound to say this isn't true. 

That's how our local electricians were able to update a house we were moving into which needed 4-wire service for the new range and dryer.

What one may no longer do (and for some time now) is to ground things to different points throughout one building - here a water pipe, there a rod driven into the ground, another one directly from the service panel. Note carefully, I said, throughout one building before you tackle me with the but...but...but, outlying building, ground rods, etc.

As to 30, 35, 40 or 50 amp service - John is right - the breaker should be the absolute lowest rating which can just carry the load reliably.

So (and let's not get into the PF discussion, yes, it's AC but it's also virtually a purely resistance load, so this is more than close enough):

30A * 240V = 7200 Watts or 7.2kW

35A * 240V = 8400 Watts or 8.4kW

40A * 240V = 9600 Watts or 9.6kW

50A * 240V =12000 Watts or 12kW

Except for one of our Flairs, I can't recall ever seeing a range really use anything near 8.4kW, much less 12kW!

Hope that helps. 

Thanks Keven, that helped.

Thank you everyone.  It would make sense to me that current installation uses 40 and wall socket should be compatible.  Replacement goal is double oven induction range. 

Hi Bob, Yes your current power supply will be fine for your new double oven induction top range.

Hi Ralph, connecting a range or dryer directly to the homes wiring is actually the best and safest way to do so. We see lots of electric ranges connected this way in condo kitchens for example. Keep in mind to do this the appliance must be installed within sight of the breaker panel in case someone is working on the appliance they would see someone that might try to restore power while servicing the appliance.

You can also install a separate cut-off switch box near the appliance and hard wire the appliance, this is what is almost always done in shops and factories with heavy equipment. A hard wired connection is much safer and more durable than trying to run 30-50 amps of power through a cord and outlet.

Every month we see at least a 1/2 dozen outlets on ranges and electric clothes dryers that burn up and fail and while I don't see the ones that actually start house fires I have seen a lot that came pretty close to doing so. So who ever hooked your range directly to the power source may have actually known what they were doing.

So very well put.

Interestingly enough, as long as six or fewer breakers have to be thrown to kill the whole service, that's good enough. You don't 'have' to have a main breaker in the NEC.

Local codes may always be stricter. Or stupider - we 'must' have an outlet and plug on our 240V equipment in our area. How much better hardwired in is! John is so right about that - and it does not good to argue with the idjiots around here. Ditto 'wirenuts'. The enormously safer, easier to use, better for many reasons including one can SEE that the connection has been made properly European style connectors aren't permitted here - despite being OK with NEC. Oh, heaven's no. They're 'metric' (seriously, that's what I was told).

Meanwhile, right across the border the young woman running their department is pushing them hard.

Sheesh.

Paulo, I already tried that, but I cannot see the little number on the circuit breaker "switch".  I'll have to ask one of my neighbors to come do that. 

John, thanks for the additional information on hard-wired connections.  I had never seen such a thing in a residential application until we pulled out that stove in 1990.

Ralph, I have heard of 1950s vintage Kenmore electric high-speed dryers being hard-wired in. 

I'd hug you if I could.  You are a lifesaver!!  I was able to take a good picture with my cell phone and blew it up and IT'S A 40 amp!!!

Almost all were direct wired back in the 50s, it was cheaper because you saved the cost of an outlet and cord, and as I mentioned before it produced a safer more reliable connection.