Conduit with 60 amp service getting warm


  #1  
Old 09-07-19, 03:14 PM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
Conduit with 60 amp service getting warm

I completed the Tesla Wall charger installation. Thanks for everyone's help on this forum.

Interesting to observe that conduit actually gets warm. 60A circuit breaker even slightly hot when touched on front. Assuming this is expected?

I used 3/4" EMT conduit, 6AWG hots and 8AWG ground. Car can charge max at 48A
 
  #2  
Old 09-07-19, 03:31 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,951 Upvotes on 3,544 Posts
You're ok. You're limited to four #6 wires in a 3/4" conduit.
 
  #3  
Old 09-07-19, 03:40 PM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
Took out a simple IR thermometer. The breaker was at 40C
 
  #4  
Old 09-08-19, 05:32 AM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
Also, I fed the stranded wire directly into breaker terminal. Should I use crimp?
 
  #5  
Old 09-08-19, 06:10 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
No need for a crimp. .
 
  #6  
Old 09-08-19, 07:56 AM
T
Member
Join Date: Oct 2005
Location: USA
Posts: 1,569
Received 74 Upvotes on 69 Posts
Most home breakers have a thermal element that is responsible for small overloads. This will warm the breaker a bit. Also, the wire screws have a torque spec that should be followed. They are to be surprisingly tight.
 
  #7  
Old 09-12-19, 05:10 PM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
I conducted some additional measurements with my IR thermometer.
I was somewhat surprised that there is a significant temperature difference between the two breakers of my 60A breaker assembly.
The one at the bottom gets to about 35C; the one on top 45C. I would expect top to be a bit hotter as heat raises, but 10C ??
 
  #8  
Old 09-13-19, 03:14 AM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: United States
Posts: 14,332
Received 877 Upvotes on 740 Posts
There is a lot of current going through the conductors. It is not surprising that the pipe is getting warm when the charger is at full load.

At 45C the breaker is within the rating of the breaker and terminals. Most newer breakers are rated at 60C or 75C.
 
  #9  
Old 09-13-19, 04:20 PM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
I guess my surprise is that the one of the breakers of my dual pole gets much warmer than other.
 
  #10  
Old 09-14-19, 05:42 AM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,523
Upvotes: 0
Received 278 Upvotes on 254 Posts
Is the conduit uniformly warm over its entire length or just at the ends?

If one half of the two pole breaker is somewhat warmer than the other, the breaker unit could be worn out or defective, with a loose connection inside. Or somehow the load out of that half of the breaker is greater, which would only occur if there was some 120 volt usage on the branch circuit.

Double check tightness of the terminal screws on the breakers (actually for all breakers and set screws in the panel) But do not use stupendous strength that could strip the screw threads.
 
  #11  
Old 09-14-19, 06:54 AM
D
Member
Thread Starter
Join Date: Jul 2005
Location: Chicago land
Posts: 702
Received 1 Upvote on 1 Post
The conduit is evenly warm over the entire length.
I will double-check the terminal screws.
The breaker is brand new..... (Siemens Siemens Q260)
 
 

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