Electrical Wiring in the Home/Surge mystery


Hi, This enquiry is not asking you to fix the problem, but to indicate what on earth (no pun intended) could be wrong. We recently bought a wood granule burner for heating our house (Italian make MCZ) and had it installed by professionals. It requires a maximum of 300 watts to heat the elements to start the fire then consumes much less to power the fan and feeder. On starting it, the elements heat and ignite the fire in 5 minutes or so as normal, then it blows the entire house electrics; not the circuit breaker trip, the main power trip. By resetting the trip quickly it will continue without problem indefinitely. We tried another outlet; same result. The vendors checked all the electrics inside and declared them OK, but sent away for an entire new set of internal electronics which they reinstalled. Same result. By trial and error we have found that it will start up fine if we use a standard 30 meter (13 amp) extension lead to any plug except the one nearest to it. Connecting it via a purpose built (13 amp) cable to the same "good" outlet yields the same result: blow out after 5 minutes. The ONLY way it seems to work is if we use one particular 30 meter extension lead. I suggested to the electrician that it seems to be some sort of back EMF when the elements cut out but this cut no ice. My only clue is that it might be a  negative spike that is partially absorbed be the resistance in the length of cable. Our house electrics were installed by a qualified electrician and work fine in all other respects. No one seems to have a clue. Any ideas?
Thanks in advance


I do not get many requests to indicate what the problem is without offering a solution, but I will attempt to do so at your request.

You could have one or more of the following problems:

1. Dead short
2. Weak main breaker
3. Too many amps for your circuit
4. Bad connection(s)
5. Bad circuit breaker
6. Old/bad wiring

It requires troubleshooting to narrow it down and find the exact problem, but troubleshooting falls under "fixing" the problem so I will leave that to you.

With some good old fashioned troubleshooting this problem should be fairly easy to discover.
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here

Electrical Wiring in the Home

All Answers

Answers by Expert:

Ask Experts


Greg Hughes


Troubleshooting electrical including appliances and HVAC.


34 years of experience.

Both college and tech schools in this field.

©2017 About.com. All rights reserved.

[an error occurred while processing this directive]