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power in my home : I keep blowing light bulbs and my dryer blows a relay

Posted on 2008-06-20
Medium Priority
Last Modified: 2008-07-10
I have just bought a 10 year old townhouse in USA , i am having an issue that i may think i have an electirical  issue , i am not a electrition but i want to test to see if i can test the electircal system in my house to make sure it is not haveing a bad ground or a fluxuation in power that is blowing things

some advice ?
Question by:kaos_theory
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LVL 13

Expert Comment

by:Nick Denny
ID: 21837125
In the first instance, before calling in the professionals, you could try a cheap plug in type meter.
LVL 39

Expert Comment

ID: 21837910
If you are not electrician, please call service. It is for your own safety.
LVL 32

Accepted Solution

aleghart earned 1408 total points
ID: 21843563
A cheap plugin meter will do nothing for light sockets or 240v dryer outlet.  This is the sort of bad advice that you do not want.

If you don't know what you are doing, you could cause property damage, injury, or even death.  It would irresponsible for anyone to suggest using the wrong tools for blind diagnostics.

Blown light bulbs and dryer tripping a circuit (you shouldn't have any relays installed in a residence) indicate wiring problems.  It's not something you can safely diagnose with zero experience.

120V lighting circuits should not be pulled off 240v feeds to dryers or ovens.  But, DIYers may have grabbed from the closest junction box.  The surge and loads from a dryer will significantly shorten the life of a light bulb, especially if it wired in-line instead of tied in with a pigtail.

Turn off the dryer.  Replace the bulb.  Turn on the circuit.  Turn on the light.  Turn off the circuit breaker.  Does the light go out?  Simple mis-wiring.  The lighting should be on a lighting circuit.

Anything beyond that simple troubleshooting requires that the dead cover be removed from your electrical panel for access to the wiring.  Also requires probing outlets while live, measuring voltage, possible measuring amperage on live hots and neutrals.  Not for a novice to attempt.  Hire an electrician.

To quote  

"Handling live electrical wires without special training and equipment is highly questionable and often fatal."

At the very least, you or an electrican will need to develop a map of the circuits.  Most areas require this by code anyway.  You can do this relatively safely (_not_ removing the panelcover or opening any boxes) with a non-contact voltage tester.  Search amazon or others for "non contact voltage".  They look like pens, have no exposed metal parts, and can be used on normal live circuits to test for the presence of AC voltage.

Every circuit breaker should be numbered and list the equipment, outlets, lights, etc. that it feeds.  Doing this first will help you (or the electrician) determine if a circuit is overloaded or is improperly shared.

To make the map, turn off all the circuits, leave the main breakers on.  Watch the should stop dead.  If it doesn't, call an electrician.  You've got wiring without the required circuit breaker.  Definitely a safety issue, and illegal.

If the meter stops correctly, turn on one circuit at a time.  Use the non-contact probe to test for presence of AC voltage at lights and electrical outlets.  You're creating circuit breaker list, but if you can note if outlets are wired incorrectly.  The grounded outlet tester noted above will do it quickly.  For non-grounded plugs that are polarized, the short slot should be hot.  The larger slot should be neutral (no voltage detected).

In a townhouse, this whole process may take a couple of hours.  Buy a couple of testers and enlist the help of another adult.  (Never encourage kids to stick things in electrical outlets.)  Do one circuit, then shut it down and do the next.

Don't be surprised if the same outlet is listed on two circuits.  If done properly, you can have two hot feeds from different circuits.  An electrican would have to remove the panel cover and check the neutral wiring and which legs the hots are on.  Keep this in mind if you are ever working on an outlet.  One circuit breaker tripped may not kill all the power to the box.

In your case, see what else is on the same circuit as your blown light.  Should not be connected to any equipment (oven, motor, dryer, heater), and should not be connected to any bathroom circuits.

After creating your circuit breaker list, consult with an electrican.  You can do the work yourself in many areas, but you'll have to pull permits in advance and have inspections from your AHJ (authority having jurisdiction).

Try the simple troubleshooting and circuit list first.  Feel free to post here, but still recommend you consult an electrician for safety's sake.

Author Comment

ID: 21980101
great awswer that was excellent , you outlined what i can do and the limits of what i would what to do in a safe enviroment . thanks so much!!!!

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