Hi,

I'm in the process of replacing a gas stove with an electric oven and
separate cooktop which has me playing with 220V current and I've got a
couple questions... I've got a 220V circuit that was run when the house was
built but never hooked up since we were using gas. I'd like to use this for
the oven, but it's not quite long enough. I'm hoping somebody can help me
answer the following:

1. Can I splice the existing 220 line to another 10 feet of cable to make
it reach?
2. Do I need a special junction box for this or can I use the same ones I
use with 110?
3. The wires are quite large. I can't imagine I'd be able to twist them
with the wires from another cable and put on a wire nut like I've done with
110 in the past. How do I join them together? A butt splice?
4. The oven manual explicitly states to attach it to copper wire. It
appears, though, that the existing wire is aluminum. Do I need to replace
the entire wire? Can I splice in copper and be fine?

Thanks,
-Doug

It can all be done. However...
You are dealing with big amperages and aluminum wire, and don't seem to know
what you are doing. That is a potentially bad combination.

I would have an electrician look at it. (Though someone here will probably
tell you exactly how to do it. Please get it right.)

Another issue (which you will probably ignore also) is that if the existing
cable is more than 8 years old, it is probably 3 conductors. You need 4
conductors to do it legally. I won't get into the issue of whether you need
4 conductors to do it safely; it is done to death here about every month.
There is no way to get around this; you have to replace the cable.

Doug Neumann wrote:
Hi,

I'm in the process of replacing a gas stove with an electric oven and
separate cooktop which has me playing with 220V current and I've got a
couple questions... I've got a 220V circuit that was run when the house was
built but never hooked up since we were using gas. I'd like to use this for
the oven, but it's not quite long enough. I'm hoping somebody can help me
answer the following:

1. Can I splice the existing 220 line to another 10 feet of cable to make
it reach?
2. Do I need a special junction box for this or can I use the same ones I
use with 110?
3. The wires are quite large. I can't imagine I'd be able to twist them
with the wires from another cable and put on a wire nut like I've done with
110 in the past. How do I join them together? A butt splice?
4. The oven manual explicitly states to attach it to copper wire. It
appears, though, that the existing wire is aluminum. Do I need to replace
the entire wire? Can I splice in copper and be fine?

Thanks,
-Doug


You need to determine whether your stove requires a neutral connection
(for the oven light, ignitors, etc.). It probably does. You need to
determine how many conductors are in the existing cable. If the stove
requires a neutral connection, and if the existing cable only has 2 hot
wires and a grounded wire, you cannot extend it and keep the current
configuration.

Do the old wires terminate in a big brown receptical? Even if there are
only 3 wires, you could still use it if you attached an extra-long cord
to the stove and plugged it into the old outlet. (This is unlikely to
be acceptable because it will be hard to hide the long cord, but I
thought I'd mention it)

If the wires are old enough, they might be tinned copper and they just
look like aluminum.

In the unlikely event that you do have 4 conductors, you can splice onto
them, and you can even splice copper to aluminum. But you have to use a
really big junction box, and the right connectors, and you have to
prepare the ends properly if they are aluminum.

If it were me, I would probably run a brand new aluminum cable (#4 or #6
aluminum type SER cable) from the breaker panel to stove and install a
NEMA 14-50R receptical right behind the stove. Then put a 4' or 6'
cord-and-plug set on the stove. This will come in handy later when you
need to remove or replace the stove -- you can just unplug it. And any
stove can be made to plug into a 14-60R outlet.

Bob

According to zxcvbob :
Doug Neumann wrote:

I'm in the process of replacing a gas stove with an electric oven and
separate cooktop which has me playing with 220V current and I've got a
couple questions... I've got a 220V circuit that was run when the house was
built but never hooked up since we were using gas. I'd like to use this for
the oven, but it's not quite long enough. I'm hoping somebody can help me
answer the following:

1. Can I splice the existing 220 line to another 10 feet of cable to make
it reach?

Yes.

2. Do I need a special junction box for this or can I use the same ones I
use with 110?

Standard 4" square boxes (not octagonal) are adequate for a simple junctin.

3. The wires are quite large. I can't imagine I'd be able to twist them
with the wires from another cable and put on a wire nut like I've done with
110 in the past. How do I join them together? A butt splice?

There are wirenuts suitable for this size.

4. The oven manual explicitly states to attach it to copper wire. It
appears, though, that the existing wire is aluminum. Do I need to replace
the entire wire? Can I splice in copper and be fine?

You _can_ splice copper to aluminum, but it's a lot of fuss. You won't
be able to use wirenuts (either special crimp-ons, or U-bolts) and de-oxidant
grease, tape, possibly a bigger box. If running a new circuit in all copper
isn't _real_ hard to do, do that.

You need to determine whether your stove requires a neutral connection
(for the oven light, ignitors, etc.). It probably does. You need to
determine how many conductors are in the existing cable. If the stove
requires a neutral connection, and if the existing cable only has 2 hot
wires and a grounded wire, you cannot extend it and keep the current
configuration.

... legally. It'd _work_, but you shouldn't.

Do the old wires terminate in a big brown receptical? Even if there are
only 3 wires, you could still use it if you attached an extra-long cord
to the stove and plugged it into the old outlet. (This is unlikely to
be acceptable because it will be hard to hide the long cord, but I
thought I'd mention it)

You shouldn't have ;-) It'd _work_, but it's not legal (there are code
max-lengths for cords to such devices (at least here), and you can't
plug in a builtin oven).

If the wires are old enough, they might be tinned copper and they just
look like aluminum.

In the unlikely event that you do have 4 conductors, you can splice onto
them, and you can even splice copper to aluminum. But you have to use a
really big junction box, and the right connectors, and you have to
prepare the ends properly if they are aluminum.

See above.

If it were me, I would probably run a brand new aluminum cable (#4 or #6
aluminum type SER cable) from the breaker panel to stove and install a
NEMA 14-50R receptical right behind the stove. Then put a 4' or 6'
cord-and-plug set on the stove. This will come in handy later when you
need to remove or replace the stove -- you can just unplug it. And any
stove can be made to plug into a 14-60R outlet.

You'd have to finesse the oven's "requirement" for copper wire. I don't
know where the instructions mean "no Al WHATSOEVER", or, "Al is fine
if you connect properly, but copper is so much easier, don't give yourself
an unnecessary headache".

For an oven, the price differential isn't that much, so I'd wire install
a new branch with copper. Unless that would be a major expense (like
major wall repair).
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

Chris Lewis wrote:
According to zxcvbob :

Doug Neumann wrote:


I'm in the process of replacing a gas stove with an electric oven and
separate cooktop which has me playing with 220V current and I've got a
couple questions... I've got a 220V circuit that was run when the house was
built but never hooked up since we were using gas. I'd like to use this for
the oven, but it's not quite long enough. I'm hoping somebody can help me
answer the following:


1. Can I splice the existing 220 line to another 10 feet of cable to make
it reach?


Yes.


2. Do I need a special junction box for this or can I use the same ones I
use with 110?


Standard 4" square boxes (not octagonal) are adequate for a simple junctin.


3. The wires are quite large. I can't imagine I'd be able to twist them
with the wires from another cable and put on a wire nut like I've done with
110 in the past. How do I join them together? A butt splice?


There are wirenuts suitable for this size.


4. The oven manual explicitly states to attach it to copper wire. It
appears, though, that the existing wire is aluminum. Do I need to replace
the entire wire? Can I splice in copper and be fine?


You _can_ splice copper to aluminum, but it's a lot of fuss. You won't
be able to use wirenuts (either special crimp-ons, or U-bolts) and de-oxidant
grease, tape, possibly a bigger box. If running a new circuit in all copper
isn't _real_ hard to do, do that.


You need to determine whether your stove requires a neutral connection
(for the oven light, ignitors, etc.). It probably does. You need to
determine how many conductors are in the existing cable. If the stove
requires a neutral connection, and if the existing cable only has 2 hot
wires and a grounded wire, you cannot extend it and keep the current
configuration.


... legally. It'd _work_, but you shouldn't.


Do the old wires terminate in a big brown receptical? Even if there are
only 3 wires, you could still use it if you attached an extra-long cord
to the stove and plugged it into the old outlet. (This is unlikely to
be acceptable because it will be hard to hide the long cord, but I
thought I'd mention it)


You shouldn't have ;-) It'd _work_, but it's not legal (there are code
max-lengths for cords to such devices (at least here), and you can't
plug in a builtin oven).

Oops. And I missed the part about it being built-in. :-/

You'd have to finesse the oven's "requirement" for copper wire. I don't
know where the instructions mean "no Al WHATSOEVER", or, "Al is fine
if you connect properly, but copper is so much easier, don't give yourself
an unnecessary headache".

Probably means the terminals are only listed for copper. If you
hardwired it, you would need all copper wire. If you use a cord and
plug, the cord with have copper or brass terminals already installed,
and it's none of the stoves business what kind of wire you used for the
receptacle.

For an oven, the price differential isn't that much, so I'd wire install
a new branch with copper. Unless that would be a major expense (like
major wall repair).

You're probably right. Definitely right if he's gonna hard-wire it. If
he uses a cord/plug/receptacle to attach, AL might make sense. (I just
instinctively think AL wire for feeder circuits and stoves, copper for
everything smaller, and the actual service wires can go either way.)

Best regards,
Bob

According to zxcvbob :
Chris Lewis wrote:
You'd have to finesse the oven's "requirement" for copper wire. I don't
know where the instructions mean "no Al WHATSOEVER", or, "Al is fine
if you connect properly, but copper is so much easier, don't give yourself
an unnecessary headache".

Probably means the terminals are only listed for copper. If you
hardwired it, you would need all copper wire. If you use a cord and
plug, the cord with have copper or brass terminals already installed,
and it's none of the stoves business what kind of wire you used for the
receptacle.

I should mention that you can always pigtail aluminum to copper IF you
do the connection correctly.

My 100A subpanel is pigtailed - obviously the electrician didn't think
it was a good idea to run #3 Al into the "used" 100A dual breaker
he had installed in the 20+ year old Commander main panel. So there's
a 4x6x6 box sitting beside the main that simply splices a short
chunk of #2 copper to the panel.

But on the other end, the Al connects direct to the (then) brand new
Seimens subpanel.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.