Checking home electrical wiring

I've just been reading about electrical fires in homes recently because of this emergency preparedness course I have been attending lately. I guess I've always been most concerned about cooking-related fires and not given much thought to electrical fires at home.

Since prevention is always better than reaction, I got to thinking about my mother's home. It's quite old, built in the 30's, and probably was not designed to provide the power that modern living demands. I'm particularly thinking about the wiring throughout the house (the fixed wiring, not things like extension cords).

In my reading, I see these comments suggesting that an electrician can check your home wiring, but I'm wondering, how can an electrician check the status of wires behind all the walls? If my mom has slowly been overloading a particular circuit and the insulation is slowly melting away inside the wall somewhere, is that actually something that an electrician would be able to find? Or is an electrician going to just focus mostly on checking the outlets and breaker box and that's mostly it?

I'm just really curious and I'd like to know what I can and can't expect from an electrician. And since reading more on the subject, I'm realizing that I should really be more aware of the danger of electrical fires since it's right up there as far as emergencies that I'm statistically likely to face at home, and most dangerous is the fact that most of these electrical fires happen when we're all sleeping.

Actually, I remember reading an article a few years ago about how universities are having to spend a lot of money upgrading the electrical systems in their dorms because today's students bring so many power-hungry appliances with them. When I was a freshman, having a PC was still very rare, and barely any of us had TV's, let alone these giant, power-hungry flat screens that we have today. A little dorm fridge and a boombox was about it in my room.

Just think about something as simple as charging a cell phone, which none of us had not that long ago. Charging one draws, what? Maybe 300-500 mA? Multiply that by every single student in the dorm and that's a lot of juice if everyone is charging their phone every night.

Just call an electrician and ask! Older homes may have different materials used for the wiring that are no longer considered appropriate. I think they used to use aluminum, but an electrician can come out and pig-tail the outlet boxes and switch boxes to take care of that. I think that's what they call it, "pig-tail". Call an electrician and ask what they do during an inspection. I'm sure they'll answer that simple question over the phone for free. If they won't, find a different electrician.

The big question would be when was the wiring done.

Not sure when them moved away from fabric covered wire, but it would have been a while. But aluminum wires enjoyed populatiry (and infamy) in the 70s and maybe 80s- if there was wiring done during that time, I'm not sure if they can use resistance or any sensory based methods to tell, but IMO it would be worth it bust to sheet rock and find out.

As for telling if insulation is warn, as far as I know not really able to tell except MAYBE thermal sensing.

Electricians can look for inferior materials and techniques by checking the fuse box or circuit breaker box, and by sampling some outlets and switchs. They can do circuit audits to make sure that circuits are not overloaded relative to the breakers in the breaker box.

They can check wiring for power leaking to the ground or neutral lines, crossed ground & neutral lines, and excessive resistance in circuits. Actually there are pretty inexpensive circuit checkers that can do some of that for you - you just plug them into an outlet and read the lights.

I'm by no means an expert, but having run power to - and installed the conduit, circuit breaker box, ground, and wiring for my horse barn taught me a lot about the topic, and helped me gain a very healthy respect for what electricians need to know. I know only a fraction of what a good electrcian knows.

The good news is that most problems have to do with the initial installation and adequacy for current loads. Over time people tend to use more power in different locations. Which leads to overloaded circuits and the use of extension cords as a substitute for a proper installation. Both of these situations lead to problems and they account for many fires.

Barring this sort of thing the vast majority of acute problems in any electrical system will be where connections are made, junction boxes and panels; where wiring is exposed to wear and tear, receptacles and extension cords; and where it is mechanically damaged.

These sorts of issues are easily spotted by a diligent inspection by a well train and experienced electrician by inspecting the wiring that is accessible.

A careful visual and electrical check of the panels, opening a representative sample of outlets and switches, and a quick visual inspection of any exposed wiring in attic and crawl spaces can go a long way to determining the health of an electrical system.

I'm no expert either....
Yes there is something known as pigtailing......but IIRC it refers to 'multiple wires' being 'twisted together' with one wire so that that wire can lead to the (outlet/socket/fixture/switch). It is done so that there is only "one" wire connected to the item. IIRC there is a limit as to how many wires can be twisted together with the one wire....

Now about the aluminum wiring.....from what I've read and been told by several electricians......DON'T PLAY AROUND WITH IT!!!!

They've told me things that (unfortunatley) I can't remember the details of....but I remember that I decided I won't touch it. Now I am NOT an electrician but have worked on may electrical projects and a number of them were on 220 lines...and I remember that what they told me basically led me to think that I didn't want to deal with the stuff.....if anyone knows more or better than I then PLEASE say so.......I'm interested too....

In the past few years, I have had several friends who were faced with completely rewiring their homes or having their homeowner's insurance canceled. According to them, homes built before a certain date were being arbitrarily selected by their insurance companies which notified the owner that their coverage would be terminated unless the home was brought up to current code. I suppose this is another incentive to update home electrical circuits.

Thanks for the replies so far. Been doing some more research. For the rather technically-oriented reader, I ran across an interesting report called How Do Electrical Wiring Faults Lead to Structure Ignitions. It's a compilation of research on the topic, which according to the authors, is actually very thin for such an important topic. Most of the research is only happening in Japan.

I too am not an electrician but have done some electrical work. Older homes can have an electrical service panel that is too small (amperage) for the needs of the home. Now that A/C, microwaves, dishwashers, clothes dryers, jacuzzi s/hot tubs are common, higher amperage service panels/and panel feeds are necessary. In some areas new homes have 200 Amp services whereas 50 or a 100 Amp service was common in older homes.

GFCI outlets/breakers are common in wet areas and ARC FAULT circuits for bedrooms are common in newer homes. Whole panel surge protectors are also common now. Very old homes had Knob and Tube wiring (no ground). Some homes had Aluminum wiring (very important to replace a fixture (outlet/switch) with ones rated for aluminum wire if that's what you have installed.

+1 on getting a trusted electrician to inspect your Mom's home for wiring issues. If any are identified, best to get a couple of estimates/opinions to ensure that what is being suggested is necessary.

We had a guy come to the factory I was working in with an IR camera. He made a video of the entire plant, all the machinery and the electrical panels.
The beautiful thing about this is it showed all the hotspots which the maintenance guy could repair. This really wasn't that expensive and it provides a great deal of peace of mind.
I think you could probably get a reduction in your homeowners as well, if you talked to the agent and sent them a DVD of the inspection.

We had a guy come to the factory I was working in with an IR camera. He made a video of the entire plant, all the machinery and the electrical panels.
The beautiful thing about this is it showed all the hotspots which the maintenance guy could repair. This really wasn't that expensive and it provides a great deal of peace of mind.
I think you could probably get a reduction in your homeowners as well, if you talked to the agent and sent them a DVD of the inspection.

It may have been in the '70's when aluminum wires were installed in many applications. Al has different thermal expansion behavior than copper so terminal boxes and connections would loosen which led to fires. May have been mitigated with Al-friendly box designs but Al wire didn't last long in the new construction world.

I despise the twisted (wire nutted) connection from a safety/reliability standpoint.

At one job the A/C circuit kept blowing a fuse in the panel for the compressors on a very, very hot summer day. I used an IR thermometer to show that one of the 3 fuses in that box was running quite hot. So we called an Electrician who tightened the terminal screw and brought the temperature back to normal. (I wasn't brave enough to work on live 220V circuits.)

The more I read about electrical fires at home, the more I realize how dangerous they can be and how they can overcome so many of these families that you hear about in the news.

Apparently most happen at night, when you're asleep, and if the problem is in the fixed wiring behind the wall, the fire can grow but you wouldn't really know it. So, eventually your smoke alarm might go off and wake you up, but you won't necessarily see fire and you dilly-dally getting out, thinking it's not so serious. Meanwhile, the fire that has been spreading inside the walls suddenly breaks through and next thing you know, you've got flames and smoke all around. Scary stuff.

And apparently the most common place in the home for electrical fires is in the bedroom, right where you're sleeping! I haven't seen any breakdown by specific causes, but probably space heaters are reason number one. Either the electric heater itself shorts out, you're using an extension cord that gets damaged or can't handle the current, or the socket or fixed wiring get overloaded. Anyway, just a guess.