Expert: Rick Miell - 4/27/2005

Question
1. Is there a way to find out if a circuit/or outlet is overloaded?
2. What is the max wattage for 15 amp and 20 amp?
3. should my lights dim when i use my garbage disposal? Its on its own circuit. thanx scott

Answer
Hi Scott.

#1:  This will require the use of an amp-meter.  This is a device that clamps around the wire, at the breaker location, and gives a reading of the current flowing on that wire.  Not usually a D-I-Y type of project.

#2:  Most breakers will handle 80% of their rating forever.  15 X .80 = 12amps.  20 X .80 = 16amps.  Going over this amount could cause damage to the insulation of the wire, which could lead to a fire.  The breaker will not, usually, trip right at their rating.  By this I mean you could apply so 25amps to a 20 amp circuit and not trip the breaker, unless it lasts for a long time.  Breakers trip from heat, so the higher the current, the more heat that the breaker will be measuring, and in time will trip out.  This is for overload, not for a short.  The current flowing throught a wire in the event of a short will be real high, and will cause the breaker to trip real fast.

3: You might see some dimming, but if it bothers you, try installing a better grade of lamp.  Some cheap ones tend to show flicker more than others.  If this doesn't solve the problem, have you electrical system checked for loose neutrals and/or phase wires.  Both could account for flicker.

Hope this has helped.

Rick Miell