Is Your Old Home’s Electrical Service Undersized?

December 15, 2015

WARNING: You may want to open your main electrical panel after reading this article. Only do it if you know exactly what you're doing.  Don't be dumb.

A high number of older homes all over the U.S. still have 60 amp electrical service.

This was fine at the time, but now it's too small to supply power for today's connected family.

In fact, this family may see the lights flicker the second they all plug in. Or have junior's favorite video game, dad’s computer data or the AC system fried by ungrounded outlets.

Today's demands put too much stress on an old 60 amp service. It'll work fine if no one tries to cook and do laundry together but come on now.   That's crazy talk.

It takes an electrician or professional home inspector to find the service size and uncover any issues inside your main panel.  Many check more than 30 things inside the main panel.

Looking Inside Your Main Panel

An untrained person should be careful even opening an electrical panel.

If you do, stand on a rubber mat or thick Styrofoam insulation.  This will keep you from getting shocked.  In fact, go ahead and don't touch anything with your free hand.  This will ensure you don't get blasted with any stray current.

Then use the knuckles on your right hand to knock on the panel to check it's not energized. Use your right hand - instead of your left - because your heart is on the left side of your body.

After, lay the back of your hand on the panel cover to feel for hot spots. If there's no arcing, popping, buzzing, or hot spots it's safe to remove the cover.

It takes an expert eye (or bundle of sample wires) to measure the wire sizes entering the box.

It also takes more than the Amp size printed on the door to determine service size.  It's even more than the main breaker size or rating of the service meter.  And no, you can't add up all the breakers inside the panel - some may be under or over fused.

Every time you work inside the electrical panel, turn off the main breaker. Now, this means your refrigerator, computers, security system, and alarm clocks will be off.

Aluminum Wiring

Inside, look for aluminum wiring. This was common in homes during the fifties, sixties, and seventies.

Look at the wires coming out of the panel. Copper wires are larger than copper and have “AL” stamped on the wrapping.  And while not unsafe, aluminum wiring does present certain issues.

First, because it expands when it gets hot, aluminum wire tends to come loose from its connections. Second, it also oxidizes so if it touches copper wiring it will corrode and overheat.

Electrical Grounding

It’s also easy to tell if your home’s electrical system is grounded. Just look for a big copper wire

clamped to the water main or a rod driven into the ground near the electric meter.

If it's disconnected, corroded, or missing call an electrician. Grounding is important because it protects against lightning strikes and shock.

In Summary

Now that we're done, leave electricity to electricians and detailed inspections to inspectors. Use this information to decide if things in your home are all good or you need to call an electrician for help.

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Steve Rodriguez

Steve is a Certified Master Inspector® and owner of Bulldog Professional Inspection Services in Kansas City, Missouri. He is the author of The Ultimate Consumer Guide To Home Inspections and has been a professional home inspector since 2003.

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