Electric Range - Copper and Aluminum Question

Reply

  #1  
Old 08-31-11, 12:06 PM
Member
Thread Starter
Join Date: Aug 2011
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Electric Range - Copper and Aluminum Question

Found some odd electric in my mom's kitchen and decided to look into things a little further. Here electric range is wired the following way:

#6 aluminum cable from the breaker to a junction box, where it ties into #10 copper with wire nuts. The circuit is protected by 30amp breaker.

Questions:

1. Is the #6 and #10 a sizing issue?
2. What is the correct way to splice copper to aluminum?
3. Are there any concerns about aluminum wiring in general?
4. What size junction box should be used? (The current box is 4x4x2)
5. The aluminum cable has two hots (I assume), and an aluminum ground. The copper cable has two hots, a neutral and a ground. Would the correct wiring configuration have the two hots from each cable spliced, and the copper neutral included with the aluminum ground and copper ground? Just want to be clear.

Thanks in advance.
 
Sponsored Links
  #2  
Old 08-31-11, 12:44 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
> 1. Is the #6 and #10 a sizing issue?

Both okay for 30A, however 30A is small for a range that may not be right.

> 2. What is the correct way to splice copper to aluminum?

With a connector rated for both with set screws or lugs. A company called Polaris makes them, and some others. Wirenuts and other "friction fit" connectors are not acceptable.

> 3. Are there any concerns about aluminum wiring in general?

The splice points are more likely to fail than copper. Care must be taken to only use devices marked for use with aluminum wire.

> 4. What size junction box should be used? (The current box is 4x4x2)

That's maybe a little small, but workable.

> 5. The aluminum cable has two hots (I assume), and an aluminum ground. The copper cable has two hots, a neutral and a ground. Would the correct wiring configuration have the two hots from each cable spliced, and the copper neutral included with the aluminum ground and copper ground? Just want to be clear.

Does the copper cable go directly to the range or is this an extension to another location in the kitchen?
 
  #3  
Old 10-01-11, 12:43 PM
Member
Thread Starter
Join Date: Aug 2011
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Ibpooks - I forgot to respond to that last question in your reply. I ended up waiting on this job, and now I've returned to it.

To answer: The copper cable ties into the aluminum and goes directly to the range outlet.

Also, and I have no idea what I was thinking in my initial post, but the cables are not #6 and # 10, they are both #8. Does that affect your response to question 1?

Thanks again.
 
  #4  
Old 10-01-11, 01:20 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
#8 aluminum is the minimum for a 30a breaker. The copper could be as small as #10 on a 30a breaker so #8 is fine.

5. The aluminum cable has two hots (I assume), and an aluminum ground.
That could be a problem because bare neutrals have not been code compliant for a long time.

Just my opinion because the breaker is undersized for a modern range and can't be increased due to the #8 aluminum plus you have a non code compliant bare neutral I'd replace the aluminum with 8-3 copper NM-b.

Aboves assumes this is intended as a 120/240v circuit not a 240v circuit.
 
  #5  
Old 10-03-11, 10:34 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Double check the wire to make sure it's actually aluminum. Many older range circuits with a bare neutral were installed with tinned SE copper cable. It looks silvery like aluminum, but if you scrape the wire you will find copper inside.

The three-wire circuit is legal if left as-is, and the copper extension may have been legal at the time of installation so it could be okay if left as-is. If you were to modify or extend this circuit it would need to be redone with four conductor copper (NM #8-3/g). The change was introduced in the 1996 code, so range circuits prior to that are usually three-wire.
 
  #6  
Old 10-03-11, 06:22 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,092
Received 29 Votes on 23 Posts
The change was introduced in the 1996 code, so range circuits prior to that are usually three-wire.


Under what version of NEC were dryer circuits changed to 4 wire, anyone know? Was it 1996, the same year as range circuits were changed?
 
  #7  
Old 10-04-11, 10:09 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Pretty sure both were in the 96 edition.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: