Temp Rated wiring questions for new fixtures

Reply

  #1  
Old 11-30-11, 01:06 PM
D
Member
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Temp Rated wiring questions for new fixtures

This was partially covered in a older, but still relevant for my project. I'm installing a pair of 90 C. temprature rating florescent lights in a bathroom redo. My question is, if I leave the existing 60 temp wire up to the wall switch then run new 90 C wire from the wall/Dimmer switch to the pair of lights (appx 4 '). Is that sufficient or do I need to provide a length of (new) wire in front of the switch? If so how much? Would it be beneficial to use armored cable from the dimmer to the fixtures ?

Thanks
Dan
 
Sponsored Links
  #2  
Old 11-30-11, 01:09 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,150
Received 87 Votes on 74 Posts
You could just rewire from the switch to the dimmer.

Armored cable is more expensive and harder for a homeowner to work with for little advantage.
 
  #3  
Old 11-30-11, 03:27 PM
D
Member
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Thanks for the quick response.
To clarify, the circuit is as follows: main breaker panel -> wall switch -> light. I'm planning on replacing the wall switch with a dimmer switch so the circuit will become : main breaker panel -> dimmer switch -> pair of lights.

Thanks
Dan
 
  #4  
Old 11-30-11, 07:03 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,150
Received 87 Votes on 74 Posts
Sounds fine.

Now would be the time to install new circuits while the walls are open.
 
  #5  
Old 12-01-11, 05:22 AM
D
Member
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Just so I'm clear, The main panel is in a different part of the house, only the bathroom walls are exposed. I'm not planing to alter the incoming (older) wire (from main) to the dimmer switch. Only replacing the wire from the dimmer switch to the fixtures.
I'm assuming the reason to do this is due to the potential for greater heat build up in the wires (due to higher amp?) associated with the new fixtures up to the dimmer switch. But the heat buildup isn't going to travel past the dimmer switch (towards the main)?? I guess I'm not clear on how far the heat will travel.

Thanks
Dan
 
  #6  
Old 12-01-11, 12:02 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 35 Votes on 27 Posts
The increased heat is from the lamp itself. It is NOT a problem with the current flow through the wiring UNLESS that current flow exceeds 15 amperes on a #14 conductor or exceeds 20 amperes on a #12 conductor.
 
  #7  
Old 12-01-11, 01:05 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,119
Received 3 Votes on 3 Posts
Don't mean to hijack here or anything...but this makes me wonder.

Since they are legislating for lower energy consumption in bulbs...which translates to less heat (esp with LED and CFL bulbs), why the requirement for higher temp insulation on the wires?
 
  #8  
Old 12-02-11, 05:30 AM
D
Member
Thread Starter
Join Date: Nov 2011
Location: USA
Posts: 4
Received 0 Votes on 0 Posts
Guys thanks for the info (probably meant ballast not lamp as these are fluorescent lights) . I suspect the higher temp rating is due to the ballast energy/heat which would likely be hidden in the wall or surrounding insulation. Energy/heat given off by lamps will be transmitted to surrounding rooms increasing to some extent increased energy costs.
 
  #9  
Old 12-02-11, 08:29 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
suspect the higher temp rating is due to the ballast energy/heat which would likely be hidden in the wall or surrounding insulation.
Ballasts are never hidden in the wall.
 
  #10  
Old 12-02-11, 09:01 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,150
Received 87 Votes on 74 Posts
Originally Posted by Gunguy45 View Post
Don't mean to hijack here or anything...but this makes me wonder.

Since they are legislating for lower energy consumption in bulbs...which translates to less heat (esp with LED and CFL bulbs), why the requirement for higher temp insulation on the wires?
This was to combat the effect of the Easy-Bake oven the heat of the bulbs was slowly cooking the life out of the insulation. After the abuse the insulation would crack and fall off the conductors.
 
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: