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-   -   Need help installing new 240V oven (http://www.diychatroom.com/f18/need-help-installing-new-240v-oven-128115/)

DanDaMan 12-29-2011 08:32 PM

Need help installing new 240V oven
 
The house we bought had a 240V wall oven. We bought a new one which I installed. When I pulled out the old oven, the oven was wired to a junction box which had 3 screw-type fuses which I believe was rated at 10amp each (30 amp total).

My question is whether the fuses are mandatory? What if I connect the red/black/white/ground from the incoming 240V wire from wall directly to the same colored wires from the oven? Why would I need the fuses since the wire from the wall is connected to breakers anyway?

Thanks

TarheelTerp 12-29-2011 08:41 PM

Quote:

Originally Posted by DanDaMan (Post 806808)
...the oven was wired to a junction box which had 3 screw-type fuses which I believe was rated at 10amp each (30 amp total).

Where are you located?
Something VERY weird is going on here

Quote:

Why would I need the fuses since the wire from the wall is connected to breakers anyway?
Is there ANOTHER electrical panel in your home?
That could be fuses or circuit breakers...

Start looking for an actual electrician.
You're probably going to need one soon.

hth

gregzoll 12-29-2011 08:53 PM

Most likely TarheelTerp, they have a very old house. It would make sense to have fuses, if the house & oven dates back to early 70's/60's. I remember the Electric stove that my parents got, when we moved into our new house in 1975. It had two screw in fuses, that were for the two legs.

As for the OP, yes you can remove the panel with the fuses, no reason to have it, where you may forget, or the next person may not know about it, and just wire like you would with a newer setup, with just the breaker. Depending on how old that fuse panel is, hang it up in your workshop or garage for a conversation starter.

ben's plumbing 12-29-2011 09:00 PM

most likley when electrial was upgraded they did not pull out oven ..just hooked feed line to new breaker ..not knowing there were fuses behind oven....yes you would not need them...ben

Bondo 12-29-2011 09:00 PM

edit,......

gregzoll 12-29-2011 09:04 PM

Quote:

Originally Posted by Bondo (Post 806844)
Ayuh,.... Not disagreein',.....
But an investigation of exactly what's Upstream from there, is important, before goin' rippin', 'n tearin'....
Ya gotta have fuses or breakers somewhere...

The reason I left that it, is that I am figuring that someone upgraded the service upstream. On board ship, we had fuse panels in various compartments to service that area, but upstream either had a load center for a group of panels, or another fuse panel. The fuse panel that the OP has, I am guessing that it was secondary protection, which would have had to been there if the house originally had fused service, or if it did not, the person that installed the old stove, most likely did it for secondary protection, for only they know why.

ben's plumbing 12-29-2011 09:07 PM

just a side thougth what is the rating on new oven....most are 40amp ?????

DanDaMan 12-29-2011 11:18 PM

Thanks for the quick replies.

A few follow ups to your questions:

- house is mid 80s vintage
- it is a big house (5200sqft) so I have 3 elec panels (and wiring is modern)
- confirmed the wiring from elec panel is 2 joined 15amp breakers so I can 30 amps feeding the oven.
- confirmed the new oven is 40 amps. What are the consequences if I leave it as-is??? I assume at worst it will trip my breakers?? If I want to upgrade, is it as easy as buying 2 joined 20 amp and replacing the breakers at the panel, or will I need thicker wiring too? I know, you will ask what guage wiring I already have, but I do not know how to measure the guage and there is no writing on the wire??

Thanks

McSteve 12-29-2011 11:42 PM

If the circuit is fed with two joined 15A breakers, it's 15A, not 30. The new oven will likely trip the breaker as soon as it's turned on. You're probably going to need a new run of #8 wire from the breaker panel to the oven, and a double-pole 40A breaker in the panel.

Stubbie 12-29-2011 11:42 PM

A few follow ups to your questions:

- house is mid 80s vintage
- it is a big house (5200sqft) so I have 3 elec panels (and wiring is modern)
-
Quote:

confirmed the wiring from elec panel is 2 joined 15amp breakers so I can 30 amps feeding the oven.
Nope you have 15 amps serving the oven. BTW that is really odd.


Quote:

- confirmed the new oven is 40 amps. What are the consequences if I leave it as-is??? I assume at worst it will trip my breakers??
Yep it's going to trip your breakers, ya ain't gonna be able to roast or bake anything...:)

You need to run an entire new branch circuit rated for 40 amps.


Quote:

If I want to upgrade, is it as easy as buying 2 joined 20 amp and replacing the breakers at the panel, or will I need thicker wiring too? I know, you will ask what guage wiring I already have, but I do not know how to measure the guage and there is no writing on the wire??
Nope you can't change breakers till you confirm the wire size but it isn't going to matter as the new oven takes 40 amps. You will need 40 amp wire.

jbfan 12-29-2011 11:47 PM

A joined 15 amp breaker is a 2 pole breaker, and it is 15 amps, not 30.
I have never seen a wall oven use 240v 15 amp circuit.
You could not change the breaker unless the wiring is large enough.

You would need to replace the wire and breaker to get the 40 amps you need for the wall oven
Somewhere on that wire is the size.


I type way too slow!!!

DanDaMan 12-29-2011 11:58 PM

Sorry, my language with electronics is not perfect.

It is a 30amp breaker (it is engraved on the flipper switch). By saying it was joined 15 amps, I assumed they were 15 each as it is one big breaker. But again it is definately a 30 amp'er.

My previous wall oven had no issues with the 30 amp service, however not really sure what it was rated at. I googled the model but it is so old that there is nothing, and there is no stamp or tag on the old oven which provides the specs.

Knowing that the new oven is 40 amp, what will be my issues if I keep the 30 amp service?? If I want to upgrade, I assume I can buy a same size 40 amp breaker and just swap. Question will be whether the wiring will be adequate??

What guage of wire is needed for a 30 amp service and what guage for a 40 amp service. Is there an easy way then for me to confirm the guage of wiring I currently have?

Thanks

McSteve 12-30-2011 12:02 AM

30A requires #10 wire, 40A requires #8. If the wiring is in a cable, the wire gauge should be printed on the outside. If it's individual wire in conduit, the wire gauge should be printed on the insulation, but may be hard to read.

If you can't figure it out, find a chunk of #10 wire somewhere to compare it to.

Jim Port 12-30-2011 12:15 AM

The two pole 15 is only for 15 amps. You do not add them together.

Since you said the new oven requires 40 amps you will need new wiring back to the panel and a new breaker.

frenchelectrican 12-30-2011 12:19 AM

DanDaMan .,

Did I catch this part that you have a 30 amp service for the whole house ??

Merci,
Marc


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