How many lights on 1 20 amp breaker?


Old 01-15-09, 05:29 AM
Thread Starter
Join Date: Oct 2008
Location: NYC
Posts: 433
Received 0 Votes on 0 Posts
How many lights on 1 20 amp breaker?

I am doing some new wiring and had a many 100w light bulbs and outlets can/should I install on 1 circuit?

Last edited by zizanio; 01-15-09 at 05:49 AM.
Sponsored Links
Old 01-15-09, 08:11 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
A 20A circuit can supply up to 2400W (120V * 20A = 2400W). Just add up the wattage of your light fixtures. Receptacles are impossible to plan for unless you have an idea of what you might be plugging in. The receptacle itself uses no power, but what you plug in makes a big difference. For example, a receptacle with a small lamp may only use 40W or 60W whereas one with a space heater plugged in might use 1800W. A vacuum cleaner uses about 1200W; which will cause a significant momentary dimming of the lights when switched on.

For this reason, it is my preference to not put lights and receptacles on the same circuit. A rule of thumb for general-purpose living spaces is to provide for 3W/square foot of lighting circuits; 8 receptacles on a 15A circuit; or 12 receptacles on a 20A circuit.
Old 01-15-09, 12:35 PM
Tolyn Ironhand's Avatar
Group Moderator
Join Date: Nov 2007
Location: Twin Cities, MN
Posts: 13,408
Received 149 Votes on 133 Posts
A 20 amp circuit is only allowed to supply 1920 watts (16 amps) continuous load. Lights would be considered a continuous load (3 hours or more).
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:
Your question will be posted in: