80 amp subpanel loads


  #1  
Old 03-28-17, 01:03 PM
A
Member
Thread Starter
Join Date: Sep 2016
Location: United States
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
80 amp subpanel loads

80 amp subpanel sufficient to handle the following loads:

1) Whole house ac unit that requires a 240v 30 amp breaker and one 240v 15amp breaker.
2) Driveway pole light with 1 outdoor receptacle 15amp breaker
3) Bathroom receptacle 20 amp breaker
4) Space heater receptacle 15amp breaker
5) Bedroom outlets 12x10 15 amp
6) 4 receptacles general use 20 amp breaker
7) 7 receptacles general use 15 amp breaker
8) Smoke alarms 15 amp breaker
9) Recessed lighting 5 ea 15amp breaker
10) Single receptacle kitchen outlet 15 amp breaker
11) 2 ea Outdoor receptacles 15amp breaker
12) Bathroom receptacle lights/fan 20 amp breaker
80 amps sufficient? Thanks.
 
  #2  
Old 03-28-17, 01:18 PM
P
Member
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,888
Received 228 Likes on 194 Posts
That's a lot of info, but can't say if the 80A is enough with that info. You need to do an estimation of the highest anticipated load you may have at any one given time.
 
  #3  
Old 03-28-17, 01:46 PM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,941
Likes: 0
Received 45 Likes on 43 Posts
Sounds like it's probably OK, but more info on the specific loads would be helpful. How many square feet of living space is covered by the listed circuits? Is there laundry or cooking appliances? Water heater(s)? Is this powering a separate dwelling unit like an apartment or duplex? If so, code generally requires a minimum panel size of 100A.

BTW, when you do a load calculation you only count the larger of the heat or A/C as they do not run at the same time.
 
  #4  
Old 03-28-17, 03:45 PM
A
Member
Thread Starter
Join Date: Sep 2016
Location: United States
Posts: 35
Likes: 0
Received 0 Likes on 0 Posts
The subpanel would not be powering a separate structure. There are no laundry appliances, cooktops, water heaters,dishwasher,garbage disposal or microwave on the subpanel. Space heater 120v hardly used. Square footage would be difficult to determine. Two circuits are part of two rooms, meaning there are other outlets in these rooms supplied by two different circuits not from the subpanel. #6 and #10 are like this. The space heater is part of #7 circuit. Not counting #6 and 10 circuits , outdoor receptacles ,smoke alarms or recessed lighting, approx 353 sq footage for two small bathrooms, bedroom and general use room which include #3,7,5 and 12. When you say use the larger of the heat or ac are you referring to the small space heater? The house heat unit is connected in the main 200 amp panel. Thank you.


1) Whole house ac unit require a 240v 30 and 240v 15 amp breaker for the ac.
2)Driveway pole light that has a one receptacle connected to it.
3)Bathroom receptacle 20 amp breaker 58 sq ft area.
4)Space heater receptacle 15 amp coonected to #7 circuit.
5)Bedroom outlets 15amp breaker 140sqft area.
6)4 receptacles general use 20amp breaker part of another room.
7) 7 receptacles general use area 120 sqft 15amp breaker
8)Smoke alarms 5ea 15 amp breaker
9)Recessed lighting 5 ea 15 amp breaker.
10)Single receptacle kitchen area 15amp breaker.
11)2ea outdoor receptacles 15 amp breaker
12)Bathroom receptacle lights/fan 20 amp breaker 35sqft area.
 
  #5  
Old 03-29-17, 08:26 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,941
Likes: 0
Received 45 Likes on 43 Posts
Sounds OK to me. Code recommends you calculate 3 watts per square foot of general-purpose load, so at ~500 sq ft you're only looking at about 15A for that portion.

You can ignore the space heater in the load calc because the AC is electrically larger.

Without doing a full calc, sounds like your 80A panel will be plenty. A 60A would almost certainly be OK too.
 
 

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