Can I run two 20A ovens off a 80A circuit?

[Edrrt]

I am replacing a wall oven from the '60s and would like to put two appliances in the space. In the back I have wiring for two hots going back to twin 40 amp breakers in the main panel that are linked together and a neutral. There's no ground.

Would it be somehow possible to run both appliances off that huge 80A wiring or install a subpanel to split it to two appliances?

My only concern with a subpanel is that it would require a ground and there's only three wires here. Ground wire is available at a nearby 110 outlet but it's much smaller gauge. Running a new ground wire all the way back to the main subhannel might be possible but would be difficult.

 

[Afjes]

A two pole 40amp breaker is not 80 amps in total it is still only 40 amps.

 

[Sponsor]

 

[Jeff H Young]

So can he use the 40 amp for 2 20 amp appliances? Im sure he would like to know and info requiring grounding . Im interested too just for general purposes

 

[wwhitney]

For "electric ranges, wall-mounted electric ovens, and counter-mounted electric cooking units" there is an allowance in the NEC to do a branch circuit tap to supply multiple units from a single 40A or 50A branch circuit.

https://up.codes/viewer/california/ca-electric-code-2022/chapter/2/wiring-and-protection#210.19_%28A%29_%283%29

Cheers, Wayne

 

[Jeff H Young]

and for a 40 amp breaker you can have 2 , 20 amp appliances ? 100 percent load. I hear they alloy 20 percent over but My guess thats for convieniance circuits or lighting

 

[wwhitney]

and for a 40 amp breaker you can have 2 , 20 amp appliances ? 100 percent load.

For a branch circuit supplying only fixed loads (not general receptacles) that is often (always?) true.

But regardless, if an oven specifies a 20A circuit, whatever extra headroom the appliance might require would already be built into that 20A spec. So a more accurate description is a 40A circuit supplying two pieces of equipment that each require a 20A circuit--they may not draw a full 20A.

Cheers, Wayne

 

[Afjes]

and for a 40 amp breaker you can have 2 , 20 amp appliances ? 100 percent load. I hear they alloy 20 percent over but My guess thats for convieniance circuits or lighting

Not really. You don't add up the ratings on appliances such as 3 appliances rated at 20amps and then think you can place them on a 60amp circuit safely. That's not how it works. A 20amp rated appliance may only be placed on a circuit rated for that appliance. The appliance will have a name plate on it listing its rating. If the name plate states rated 20amp OCD (o.ver c.urrent d.evice, breaker) then you can't place it on a 40amp circuit. You can smoke the appliance if a fault occurs as the breaker won't trip.

 

[WorthFlorida]

The circuit you have is for a 220v appliance only. Code today requires a ground but all ovens, ranges and electric dryers do allow for the three wire connection for the million of homes wired with three wired 220v circuits. Follow the appliance installation instructions.

Placing a sub panel would be a problem since you have to have access to it and there are clearance requirements for panels and grounding. The circuit breaker you have are maybe be a single lever or a double lever with a pin tying the two together. For two separate circuits the pin can be removed. A single level the breaker would need to be changed.

NEC prohibits a branch circuit to be on two separate runs (conduits, raceways, cables). All wires for the one branch circuit must be run together, therefore, you cannot use a ground from another circuit that is not part of the 220v circuit you have, though electrically it will work it can be dangerous.

FYI, the circuit breaker protects the wiring, not the appliance. If the appliance calls for a 20 amp circuit, it's the minimum to prevent false tripping. You can use a 40 amp circuit but making wiring connections for an outlet or direct wire can be troublesome. Connecting an 8 gauge wire to a 12 gauge is usually difficult and must use the correct connectors.

 

[wwhitney]

NEC prohibits branch circuits to be on two separate runs (conduits, raceways, cables).

There are exceptions for the case of non-metallic wiring methods, like NM cable or PVC conduit.

All wires for the one branch circuit must be run together, therefore, you cannot use a ground from another circuit that is not part of the 220v circuit you have, though electrically it will work it can be dangerous.

There are also exceptions allowing a separate EGC (ground) to be run to retrofit existing ungrounded circuits. Having the EGC physically separated from the circuit conductors might increase impedance during a fault, but it will certainly be better than having no EGC.

Cheers, Wayne

 

[Jeff H Young]

Not really. You don't add up the ratings on appliances such as 3 appliances rated at 20amps and then think you can place them on a 60amp circuit safely. That's not how it works. A 20amp rated appliance may only be placed on a circuit rated for that appliance. The appliance will have a name plate on it listing its rating. If the name plate states rated 20amp OCD (o.ver c.urrent d.evice, breaker) then you can't place it on a 40amp circuit. You can smoke the appliance if a fault occurs as the breaker won't trip.

I was thinking a sub pannel was going in With 2 20 amp breakers but follow you , yes 40 amps is plenty but he needs protection for each device at 20 amp , so it sounds