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Re: Safe capacity of a 15 Amp circuit... Posted by TML [Email]  (#2212)  [Profile/Gallery]
(more from TML) on Wed, 20 Jan 2010 14:44:53
In Reply to: Re: Safe capacity of a 15 Amp circuit..., jp498, Tue, 19 Jan 2010 18:36:00 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Just to put some of this into perspective, let's do some calculations. I will even ignore the fact that any device with a 15A rating is going to draw less than it's maximum rating, typically 20-40% less.
First of all, there will be voltage drop in ANY circuit, provided there is current flowing, regardless of the wire size. So saying "voltage drop is bad for motors", without quantifying it is a pretty meaningless statement.
14AWG wire has a resistance of 0.0025ohms/foot
For a typical installation of say, 50 feet, we have the following for voltage drop:
0.0025*50*15 = 1.9V , or 1.6% drop (so if you start with 120V, you then have 118.1V)
How does this compare to running a 20A circuit?
0.0016*50*15 = 1.2V, or 1.0% drop (120V down to 118.8V)
The difference between the two is 0.7V. The comparative power loss between the two is 10W.
It's hard to estimate how much re-wiring would cost, but I think $500 would be pretty conservative. At $0.08/kWh, that equates to 625000 hours of continuous use to equalise the upgrade cost. Running at 24/7, that's a 71 year payoff.
posted by 216.13.111...
, Tue, 19 Jan 2010 10:38:15, Wed, 20 Jan 2010 14:13:50, Wed, 20 Jan 2010 14:44:53 <-- Viewing This Message
, Sun, 17 Jan 2010 07:46:04, Sun, 17 Jan 2010 16:38:05
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