ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Recent Posts
Using THWN on automotive circuits
by BigB - 03/23/23 11:19 AM
Continuous load
by HotLine1 - 03/08/23 02:11 PM
How's all our Non-US folks doing?
by dsk - 03/08/23 11:56 AM
Old Computers?
by Bill Addiss - 03/04/23 05:06 PM
New in the Gallery:
Burger King crown sillyness
Burger King crown sillyness
by wa2ise, December 11
240/208 to a house
240/208 to a house
by wa2ise, October 9
Who's Online Now
0 members (), 28 guests, and 17 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#41288 08/24/04 04:14 PM
Joined: May 2004
Posts: 49
jayson Offline OP
in a house panel with a 100 amp main can u put a 100 amp breaker on the bus . like if in the panel i have 2 20 amp lighting circuit breakers and 30 amp and 50 amp range and a 100 amp below that feeding central air unit.any help would be aprecicated thanks

#41289 08/24/04 04:23 PM
Joined: Jan 2004
Posts: 66
you should not have a 100 amp breaker on the A/C it should be 20, 30, or 40 amps depending on the A/C units rating

#41290 08/24/04 08:18 PM
Joined: May 2003
Posts: 2,876
e57 Offline
60A tops if the thing (AC) is a real beast, sounds sketchy?

Mark Heller
"Well - I oughta....." -Jackie Gleason
#41291 08/24/04 08:36 PM
Joined: May 2004
Posts: 697
Typically, the wire is sized to the load, and the breaker matches the wire size. There are other circumstances, of course. What is the air conditioning load, and the wire gauge?


#41292 08/24/04 09:47 PM
Joined: Apr 2002
Posts: 914
It is posible to have a 100 breaker for A/C, it's very common around here to have a 100 amp breaker serving a disconnect for 3 or 4 A/C units rather than having 3 or 4 diferent home runs for each unit.

To answer the guy's original question, yes it is posible, but if the A/C's draws a combined load anywhere near that 100 amps, it's too much for the panel with all the olther stuff.

#41293 08/24/04 10:16 PM
Joined: May 2004
Posts: 49
jayson Offline OP
the 100 amp breaker is feeding a diconnnect with a 60 amp breaker.

#41294 08/25/04 09:36 AM
Joined: Aug 2001
Posts: 16
What size is the wire?

#41295 09/03/04 02:53 PM
Joined: Jul 2002
Posts: 241
SJT Offline
Do you have a range and a dryer on this panel also? It sounds like you need to upgrade to a 200 amp service. Things would be OK, but then the 60 amp load of the AC arrives on the scene.
Very possible the main could trip. Is it worth living with that chance?

Link Copied to Clipboard

Tools for Electricians
Tools for Electricians

* * * * * * *
2023 National Electrical Code (NEC)
2023 NEC Now Available!
* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman


Member Spotlight
Atomic City, ID USA
Posts: 806
Joined: October 2004
Top Posters(30 Days)
BigB 3
triple 2
Popular Topics(Views)
305,112 Are you busy
233,510 Re: Forum
218,193 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5