Replacement heater wiring problem

[TonyN]

Hello all,

I am replacing the wall-mounted heater in a room in my house. It is a 240V convection heater, latest model, replacing a 10 year old unit that stopped working.

It mounts on a wall that is about 2' high below some large windows (see picture 1). The wall itself is only about 6" thick, and is packed with insulation.

The previous heater had all of its wiring 'internal'. The wire came out of the wall (see picture 2) and it got all connected, etc. inside the heater.

However...

The new heater wants to connect via an electrical box, where the power wires and the wires from the heater would connect (see picture 3).

My dilemma is that I cannot mount a box in this wall. The problems are: it is packed with the pink insulation with a vapour wall, I would have take large chunks of drywall out, the wiring was run to one place because that's where the heater was.

I did consider running the wiring into the new heater like it was in the old. However, after taking the cover off and investigating, it won't work.

What are some options here? Is there such a thing as an electrical box that can sit outside the drywall? Any other neat ideas?

Thanks,

Tony

Picture 1

Picture 2

Picture 3

 

[nealtw]

They make a box to fit in the drywall and yes you deal with the vapour bearer too.
http://diy.stackexchange.com/questions/27605/how-do-i-retrofit-a-junction-box-in-an-insulated-wall

 

[bud16415]

Your wire coming out of the wall looks to be 120V. Are you sure your old unit was 220V.

Not clear on what you are showing us about the new heater why it can’t be wired like the old one also.

Welcome to the forum.

 

[JoeD]

Your wire coming out of the wall looks to be 120V.

What makes a 120 wire look different than a 240 volt wire?

 

[doechsli]

My limited knowledge would think there should be three leads (2 hots and a neutral) and a ground for 220V not just two and a ground.

 

[afjes_2016]

Your wire coming out of the wall looks to be 120V. Are you sure your old unit was 220V...

There is no way to tell for sure by just looking at this picture if this is a 120v or 240v circuit; (a hint would be if the white wire was remarked with black tape, marker etc indicating the white is being used as a hot wire and not a neutral which is dictated by code but not many people do this unfortunately). The only way for sure is by putting a meter to it. Just because there is a white wire it can not be assumed that it is a neutral. Any time I hook up a 240v circuit I use a 2 wire with ground. If it is a 120/240v circuit then you will have a black, red and white most times as in a Romex cable.

...Not clear on what you are showing us about the new heater why it can’t be wired like the old one also.

Welcome to the forum.

I believe what TonyN is stating that the old heater had an internal wiring compartment where the splices were made. The new heater does not have that so therefore since the splice must be contained within a compartment, in this case a device box of some type he is asking for suggestions as to what type of box to use in order to not compromise the integrity of the vapor barrier and insulation within the wall.

TonyN are you sure this is a 240v circuit? Are you sure the new heater is a 240v heater?

 

[afjes_2016]

My limited knowledge would think there should be three leads (2 hots and a neutral) and a ground for 220V not just two and a ground.

A simple misconception that many people make. Your description would be for a 120/240v circuit or a multi-wire branch circuit.

 

[bud16415]

What makes a 120 wire look different than a 240 volt wire?

I guess that was my way of asking the question have you measured the voltage across the black and white , white to ground and black to ground. His new plug looks to have at least 4 wires read green white and black with a cover plate attached. What he doesn’t show is the other end of the wire and if there is an access panel where he could terminate the wires eliminating the feed wire. My thought is there would be. Or possibly could be.

I don’t know what current code is with wall heaters and no common on a 220V heater. I know you can’t get a dryer installed around here any longer without a RBWG pigtail and outlet.

 

[afjes_2016]

...I don’t know what current code is with wall heaters and no common on a 220V heater. I know you can’t get a dryer installed around here any longer without a RBWG pigtail and outlet.

Current code specifically states that there must be two hots, a neutral and a ground on new installations. The old way that stoves were wired also was two hots and a ground (service entrance cables were usually used) which actually was used as a neutral and then there was a strap placed on the wiring deck of the dryer/stove from the ground of the stove to where the ground from the panel was connected (neutral spot). This utilized the NEMA 10 30R or NEMA 10 50R; now it is required that there be two hots, neutral and a ground. In this case then using a NEMA 14 30R or NEMA 14 50R (3 pole 4 wire). The reason why there is a neutral in the case of the dryer or stove is that each requires a 120v supply; example: The dryers timer, tumbler, digital display, etc requires just 120v, where as the heating element required 240V. Same thing with a stove. Some of the stove top elements depending on the size would either run on 120v or 240v and the oven/broil elements required 240v, digital display 120v. Again you would need a neutral for this. In the case of a wall heater, baseboard heater or the like they are mainly just 240v and therefore a neutral is not needed because you just need two hots and a ground, this also applies to a standard electric household hot water heater, this is strictly 240v so no neutral is needed. When I first learned about this I had the misconception that all 240v units, stoves, dryers heaters whatever would always require two hots, a neutral and a ground until I understood better the theory.

 

[bud16415]

Thanks for the detailed explanation afjes_2016.

So in this case if the OP’s heater has controls on it fan or heat selection the control voltage would have to be 120v and the OP would be required to run a new cable?

 

[TonyN]

Confirmed it is a 240 Volt line and Heater.

Nealtw's post about the drywall box and vapour barrier is the one I am going to go with.

Thanks all for your help.

Tony

 

[afjes_2016]

Thanks for the detailed explanation afjes_2016.

So in this case if the OP’s heater has controls on it fan or heat selection the control voltage would have to be 120v and the OP would be required to run a new cable?

You are welcome.

No not necessarily. What the OP needs to do is know for sure (reading the name plate on the heater or the enclosed instructions) that the heater is in fact a 240v heater. If it is a 240V then it must be connected to a 2 pole breaker (white wire and black wire both connected to the breaker, white wire colored black or with tape to indicate it is hot), no neutral connection and of course a ground is required. If it is a 120V heater then it must be connected to a single pole breaker, black would be hot to the breaker, white would be connected to the neutral bar and ground to the ground bar. Either way 120 or 240v the existing cable (Romex) may be used because more than likely it only requires either 120v or 240V circuit even though it may have a fan. I have fan forced hot air heaters in my house. They all run on 240V. Very important before hooking anything up, know what the voltage is that is required. Again, name plate is important. Must know voltage before connecting. Some people assume because it is a heater it is a 240v.

Hope this clarifies it.

 

[nealtw]

You are welcome.

No not necessarily. What the OP needs to do is know for sure (reading the name plate on the heater or the enclosed instructions) that the heater is in fact a 240v heater. If it is a 240V then it must be connected to a 2 pole breaker (white wire and black wire both connected to the breaker, white wire colored black or with tape to indicate it is hot), no neutral connection and of course a ground is required. If it is a 120V heater then it must be connected to a single pole breaker, black would be hot to the breaker, white would be connected to the neutral bar and ground to the ground bar. Either way 120 or 240v the existing cable (Romex) may be used because more than likely it only requires either 120v or 240V circuit even though it may have a fan. I have fan forced hot air heaters in my house. They all run on 240V. Very important before hooking anything up, know what the voltage is that is required. Again, name plate is important. Must know voltage before connecting. Some people assume because it is a heater it is a 240v.

Hope this clarifies it.

Don't forget the thermostat that may be inline.

 

[afjes_2016]

...I don’t know what current code is with wall heaters and no common on a 220V heater...

Just a friendly correction in terminology. The white wire which is used as a neutral is not referred to as a "common" but a neutral.

Also, now in today's voltages, no more 110v and 220v, it is now 120v and 240v. Again, just a terminology correction in good taste.

 

[nealtw]

I would be more concerned about how many wire are coming out of the new heater.

 

[afjes_2016]

Don't forget the thermostat that may be inline.

Yes, absolutely correct; however some heaters have their own thermostats within the unit, such as my wall heaters. But let's say electric baseboard heaters that are generally used in homes. They can have either an "on-board" thermostat, meaning on the heater it self or a wall in line thermostat as you suggested. You can also set some up with low voltage thermostats, but let's not go there now.

 

[afjes_2016]

I would be more concerned about how many wire are coming out of the new heater.

Yes, again you are correct. This is what they taught us in electrical class - "Always read the directions!!" then we would know what all the wires are for coming out of the heater and not just assume. We all know what happens when we assume :nono:

 

[bud16415]

Just a friendly correction in terminology. The white wire which is used as a neutral is not referred to as a "common" but a neutral.

Also, now in today's voltages, no more 110v and 220v, it is now 120v and 240v. Again, just a terminology correction in good taste.

I guess I’m showing my age. 50 years ago it was 110/220 then it was 115/230 and now it is 120/240. That was when there was no ground just hot and common. If the voltage gets any higher I’m going to be afraid to work on it.

 

[afjes_2016]

I guess I’m showing my age. 50 years ago it was 110/220 then it was 115/230 and now it is 120/240. That was when there was no ground just hot and common. If the voltage gets any higher I’m going to be afraid to work on it.

My age is getting there too. :agree:

Be afraid; never!! Before I took my electrical classes I was scared to death of a breaker panel or any electric. When graduated I learned the difference; don't fear electric, respect it!!

 

[nealtw]

My age is getting there too. :agree:

Be afraid; never!! Before I took my electrical classes I was scared to death of a breaker panel or any electric. When graduated I learned the difference; don't fear electric, respect it!!

For the rest of us, fear will work just fine thanks.:thbup: