Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Sub-Panel installation question. Furnace wire to run sub panel???? maybe?

Sub-Panel installation question. Furnace wire to run sub panel???? maybe?


  #1  
Old 12-27-14, 12:07 AM
D
Member
Thread Starter
Join Date: Dec 2014
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Sub-Panel installation question. Furnace wire to run sub panel???? maybe?

I am new to electrical. I have a basic understanding but not vast. I know I need to install a sub panel for the work I will be doing in my home. The question is can I use the power line that currently runs to the furnace to supply the sub panel, then run the furnace off the sub panel. I am thinking this becasue it would be cleaner to avoid ripping down things and I want to put a sub panel next to the furnace anyway for a welder in the garage and some lighting in the basement. Also to save th cost of buying wire which I am sure is expensive.

The furnace runs off of a 90amp breaker. The wire to the furnace from the 90 amp breaker is E32071 (U L) 2-2-2 AL. TRIPLE - E ALLOY TYPE SE CABLE STYLE U TYPE XHHW CDRS 300V. TO GROUND.

This is overkill isnt it but can I do it?

The panel will supply power to

Furnace: 208/230 Volts
Dual Supply Circut
L1/L2 Heater Amps 36.2/40.0 Miin. Ampacity 53.8/58.5
max overcurrent protection 60/60
L3/L4 Heater Amps 18.1/20.0 Min. Ampacity 22.8/25.0
max overcurrent protection 25/25


Welder: 220Volt / 60 Hz / Single Phase / 24.5Amps 3-Prong, 220V AC, polarized, twist lock NEMA#L6-30


2-3 outlets in Garage and a couple on the inside of the wall inside if It is possible.
possibly a bathroom.


Any advice would be apprciated.
I can comprehend everything I have ever been told so far about electrical so I am 100% positive I can understand whatever you throw at me.

thanks!
 
  #2  
Old 12-27-14, 06:35 AM
W
Member
Join Date: Jun 2008
Location: VA.
Posts: 765
Upvotes: 0
Received 1 Upvote on 1 Post
No, you can't use the existing cable for a sub panel.

Your existing cable is type SEU which only contains 3 wires.

You'll need type SER for a sub panel, which contains 3 insulated conductors and a bare ground.
 
  #3  
Old 12-27-14, 08:30 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,870
Received 185 Upvotes on 166 Posts
The furnace circuit has no neutral conductor, just 2 hots and 1 ground. It appears you have a 2 circuit 15 KW electric furnace. I am wondering how those 2 circuits are powered by one 90 amp circuit. Since your SEU cable is only rated 300 volts to ground, I am assuming this installation is from the '80s or earlier.
 
  #4  
Old 12-27-14, 09:07 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,970
Received 194 Upvotes on 170 Posts
In addition, the circuit for your air handler should remain dedicated.
 
  #5  
Old 12-27-14, 10:16 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,278
Received 861 Upvotes on 724 Posts
The furnace running at full tilt will draw about 83 amps. There is not any ampacity available on that circuit.
 
 

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