How much current can I draw safely from one outlet?


Old 11-04-07, 09:08 PM
Thread Starter
Join Date: Nov 2006
Location: San Francisco, CA
Posts: 139
Upvotes: 0
Received 1 Vote on 1 Post
How much current can I draw safely from one outlet?

How much current is it safe to draw from a single outlet on a 15 amp (old!!) circuit?

Our house was originally wired in the late 50's. So most circuits seem to be run with some sort of fabric covered wire, with ceramic looking donuts whever the lines run through wood. In the 80's the fuses were converted to breakers, and new (plastic unsulated?) circuits were added.

I want to power approximately 560W peak (500W continuous) of electronics from a single outlet that is on one of the older 15 amp fabric insulated circuits. Am I asking for trouble? This seems like about 1/3 the capacity of the entire circuit.
Sponsored Links
Old 11-04-07, 09:18 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Upvotes: 0
Received 13 Votes on 11 Posts
Since the circuit is ungrounded and you want to run electronics the best practice solution would be a new grounded 20 amp circuit. Yes one third for the older circuit as you said but more importantly what is or may occasionally be on it. Best to just run a new circuit.
Old 11-04-07, 09:23 PM
Join Date: Aug 2004
Location: NA
Posts: 1,065
Upvotes: 0
Received 1 Vote on 1 Post
What you have is knob and tube wiring with no ground. In good condition this wiring is fine. A 15 amp circuit that supplies two or more outlets it is recommended that you do not use more than 12 amps at any one 15 amp rated outlet for cord and plug equipment. A duplex receptacle is 2 outlets. Accordingly any one cord and plug piece of equipment should not exceed 12 amps on a 15 amp rated branch circuit.

Old 11-04-07, 09:38 PM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 19,290
Received 44 Votes on 41 Posts
General rule is no more than 80% of the max rating on the breaker - 12 amps is 80% of 15 in this case.
Old 11-05-07, 05:54 AM
Join Date: Sep 2002
Location: welland ontario
Posts: 6,562
Received 67 Votes on 62 Posts
Full loaded 15 amp circuit is 1800 watts. You are not even close to that. It should not be a problem depending on what else you have on the circuit.

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
Display Modes
Ask a Question
Question Title:
Your question will be posted in: