Heat pump disconnect

Reply

  #1  
Old 11-28-12, 10:30 AM
D
Member
Thread Starter
Join Date: Aug 2012
Posts: 16
Received 0 Votes on 0 Posts
Heat pump disconnect

Quick question: Do I use a Non-Fusible or fusible disconnect outside next to my heat pump? Or does it matter.

Thanks,
Dano
 
Sponsored Links
  #2  
Old 11-28-12, 10:38 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,144
Received 84 Votes on 72 Posts
Unless your instructions for the unit call for fuse protection you can use a non-fused pullout disconnect.
 
  #3  
Old 11-28-12, 06:12 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 10,638
Received 84 Votes on 74 Posts
There is a definite application for a fused disconnect, but it doesn't occur that often in residential work. Assuming you have a 50 amp circuit, if you have reently replaced your old unit with a new higher efficiency unit, the manufacturer may call for a MOCP of 35 amps or 45 amps. In these cases, you would use the fusible disconnect and fuse it to match the MOCP rating. Most residential heat pumps and A-C condensing units operate with between a 20 and 40 amp circuit. Many times the circuit breaker size can just be reduced to match the MOCP rating on the new unit.

Some units don't use the MOCP terminology, but will list a "Maximum Fuse Size". I have seen some inspectors who see this different terminology and then require fuse protection at the disconnect rather than allowing the circuit breaker to provide the protection.
 
  #4  
Old 11-28-12, 07:52 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,144
Received 84 Votes on 72 Posts
If the unit says fuse protection you cannot have just the breaker to protect the circuit.
 
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
 
Ask a Question
Question Title:
Description:
Your question will be posted in: