Electric: What to Look for When Buying an Old Home

Electric: What to Look for When Buying an Old Home

Home Inspections

“Electric" is part of our series on

Old Home Inspection Checklist, a Homeowner’s Guide

You are considering buying an older home – one that was built prior to 1950.  Our Home Inspection Checklist for Old Homes was developed for the prospective home owner to use on the first serious walk through to get to know what assets or problems the old gal might have. When you check out the electric in the house, the top three things to look for are the electrical service box, if there is knob & tube wiring and if it has grounded receptacles.

Kelley Moore, Lifestyle Expert and a home restoration junkie sat down with Joe Gonzalez of  Joe’s Electric, Walla Walla, Washington  to talk about the top three tips when checking out the electric system in an old home.

Electrical Service:  This means the power box on the side of the house that feed power to your house.  This is usually in conjunction with the meter from your electric company.  Please don’t touch this, but do ask when it was updated last. When the licensed electrician inspects the house, he will look at this and the electrical panel that usually is in the garage or basement more closely .

Knob and Tube Wiring:

If you are an old home aficionado, you might be familiar with this.  Knob and tube is the earliest form of electrical wiring most commonly used in buildings in North America from 1880 through 1950.  It is made up of ceramic knobs that holds wires that are contained in a rubber coated cotton fabric.


  • It is relatively safe if it has been maintained properly. However, it was designed for basic lighting purposes and the amount of electric devices such as air conditioning, computers and stoves could very easily overload the system.
  • Knob & tube needs to be kept cool with air circulating around it.
  • If modern insulation has been installed over it, it can cause overheating which could result in a fire.
  • Insurance companies may not issue insurance because the wiring is old and the insulating rubberized cloth can crack.
  • Insurance companies also don’t like the fact that knob & tube does not have a grounding conductor, which directs excess electrical surges into the ground and serves as  a safety system.
  • Since it is not grounded, knob & tube cannot handle three pronged plugs.
  • Knob & tube around water, as in the kitchen and bathrooms, can be very dangerous – any electric is. That is why GFI outlets are used today.
  • If too many appliances are run at once in the house, it can cause a surge in power, which can result in a fire.

Grounded Receptacles:

If your outlets do not have GFI or GFIC (ground fault circuit interrupters) in areas that have water or extreme moisture, replace them.  GFI’s  balance the flow of electricity from the outlet to the appliance you are plugging it into.  Without a GFI outlet, if incompatible, it could result in an electrical shock, spark or overload on your system, which will cause the power breaker to ‘short’ or turn off.

Yes, GFI outlets can be used with knob & tube wiring, but alike anything thing else, consult your electrician first.

Before you sign on the dotted line, have a Licensed Electrician inspect the house.
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