File This Away: Don’t Alter Polarized Plugs


QUESTION: Can I file down the wide tip on a polarized plug without bad effects?

ANSWER: No! Inserting a polarized plug the wrong way around, which becomes physically possible when you file down the wide prong, could create a shock hazard by making the appliance cabinet live even when the switch is turned off. The slots in a polarized receptacle are different sizes to prevent this very thing. The wide slot is connected to the neutral wire and the narrow one to the hot wire. The polarized plug ensures that the inlet side of the appliance switch is connected to the hot lead. This keeps components beyond the switch inside the appliance from being electrically hot when the switch is turned off.

If you have nonpolarized outlets and need to plug in a polarized appliance such as a TV set, don’t ever file down the wide plug prong. Instead, you should replace the receptacle with a polarized outlet and make sure it has been wired correctly with the neutral wire going to the terminal for the wide prong and the black hot lead going to the one for the narrow prong.

Water Tank Residue Should Flush Out Soon


Q: Our hot-water storage tank recently leaked and was replaced by another stone-lined tank. My family and I noticed an unsettling change in the feel and texture of the water in the shower and sinks the evening of the installation. My wife describes the water as feeling slimy or soft. I thought it felt more silky, such as diluted mineral oil or water that had cement residue mixed in with it. Nevertheless, the water was nice and hot.

What can you tell us about stone-lined hot-water storage tanks? Will the residue rinse away with time and is it a health hazard?

A: The term stone-lined is really a misnomer. The storage tank is actually lined with concrete. Probably, the company that manufactured your unit uses a fine sand in the concrete mix, which has the texture of flour.

You were on the right track when you said the water had a cement-residue feel to it. Any tank residue should flush out shortly. If it doesn’t, contact the manufacturer.


There is nothing inherently unsafe with stone-lined hot-water tanks, but if you are concerned, you can have the water tested.

Plastic Pipe Can Disrupt Grounding

Q: We recently had some plumbing repairs done by a local handyman. He installed some plastic pipe in our domestic water supply system. A neighbor looked at the job and said the repair compromised the main ground connection in our home’s electrical system. Do we have a problem, and if so, how can we correct it?

A: Most electrical codes require a home’s electrical system to be grounded through the copper or galvanized-iron water supply pipes that lead from the water main to your faucets. This is done by clamping the ground wire from the panel to a pipe. A problem can arise, however, when this continuous ground is disrupted by splicing a length of plastic pipe in the water system.


Though not allowed by code in most areas, plastic water piping has enormous appeal to those uncomfortable with traditional piping materials and methods. If a part of your home’s water supply piping has been replaced with plastic, you can still have the protection provided by a proper and legal ground.

To reestablish the ground, simply fasten approved grounding clamps to the metal piping on each side of the plastic splice. Then span the gap with a short length of No. 4 solid ground wire. Bind the wire tightly in the clamps and the job is complete.