cooktop wiring

When our cooktop needed to be replaced, I thought, Even though I know little about electric wiring, how hard can it be to install a new one myself? I'll simply copy the existing wiring connections. Turns out the first cooktop had four wires (red, black, bare, white) which match exactly the 4 wires coming into the box, but the new cooktop has only three (red, black, bare). What happens with that white wire in the wiring box? Does it remain connected to nothing and get capped off or taped up? Or do I have an incompatible cooktop? Thanks for the help. Timo
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

When I did this, my cooktop had the same number of wires. Typically red and black are single phases used to get 220/240 volts; white is neutral; and bare is ground. Is there anything on your old cooktop, like a light or a display? The neutral is used to generate 110/120V. Is there any difference between the old and new cooktops? You may be able to cap off the neutral, but I'd guess that you have the wrong cooktop.
--
Bob in CT
Remove ".x" to reply
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Old one is 220, is new one 110 ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If the new cooktop doesn't use the white <neutral> you can just cap the one coming out of the cable feeding it. If there are no 120v loads in the cooktop, like a clock, light or whatever there is no need for the neutral. My new slick top doesn't have any 120v loads either.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As others have mentioned, if the new cooktop has no 120V loads (eg: fan, timer etc) it may be a 240V only unit, and not need the white neutral (which you can just cap off in the distribution box).
However, it is remotely possible that the new unit is convertible between the old 3-wire (combined neutral and ground) and new 4-wire NEC requirements on stoves, and you need to "reconfigure" the cooktop for 4 wire connection.
Check the wiring instructions for the new unit or call the manufacturer to be absolutely certain.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ding ding!!! and it only took 4 people answering!!
all you need to know is in the instalation manual that came with it.
randyu

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Mine didn't come with an installation manual. There was nothing but the cooktop. In my case, installation was a snap as it used plastic connectors. There really was no need for an installation manual.
--
Bob in CT
Remove ".x" to reply
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


Oft-times these things are expected to be installed by qualified electricians who don't need to have detailed installation manuals, and already know the fiddly details. Doesn't mean that they're necessarily straight-forward to someone who hasn't done it before.
You mean it didn't have a counter-cutout template? Ducting specs? Clearance specs? Supply circuit specs?
Remind me not to buy one of those. Ick.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks to all for their suggestions. While the unit does come with an installation guide, and there is also a diagram attached to the metal hose leading out of the unit, neither was really clear (to me, in my inexperience) what should be done with the white wire. The installation guide says "You must use a two-wire three conductor 208/240 VAC, 60 Hertz electrical system. A white (neutral) wire is not needed for this unit." But that didn't tell me what to do with the white, only that it wasn't to be connected to the unit. The wiring diagram presupposes there are only three wires in the box and doesn't even show the white. My guess was that it could be capped off, but I wasn't sure if that would "hurt" anything. I will call the mfgr as suggested, to be safe. Regards Timo
: ding ding!!! and it only took 4 people answering!! : : all you need to know is in the instalation manual that came with it. : : randyu : : > Check the wiring instructions for the new unit or call the manufacturer : > to be absolutely certain. : :
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Fold it back on itself and wrap some tape around it. That indicates a spare wire to an electrician. Then put it in the back of the box.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Isn't needed means the unit does not need a white (neutral) connection. It the wire is long enough, you might also cut off the bare copper part of it, then tape it securely and put it back into the box for any future use. The third conductor that IS needed must be a green or bare wire. --Phil
Timo wrote:

--
Phil Munro Dept of Electrical & Computer Engin
mailto: snipped-for-privacy@cc.ysu.edu Youngstown State University
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks to Phil and Greg for their detailed explanations. I appreciate the help. Timo
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.