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Hubbell Twist-Tite outlet

A friend bought an old house recently, and he came across an odd outlet. He asked me to look at it, wondering what it was, and if it was even AC. He thought it might be high voltage DC, a holdover from a very different time. It turned out what he had was a Harvey Hubbell Twist-Tite outlet.

What is a Harvey Hubbell Twist-Tite receptacle?

Hubbell Twst-Tite Outlet

This Hubbell Twist-Tite outlet is an uncommon sight today but a 2-prong plug will fit in it if you ever encounter one.

A Hubbell Twist-Tite receptacle takes a special plug that you can twist to lock it in, like some modern high voltage outlets. But it’s backward compatible with a standard 2-prong 115 volt US plug. At least the non-polarized version. So it’s fine for plugging in, say, a lamp. But lack of a ground plug limits its utility to a degree.

The Twist-Tite was common in military applications in the 1940s, for plugging something into a generator in the field and making sure it stayed plugged in. Most likely, a lot of these turned up as government surplus after WWII, which is one reason you can find these in old houses. Local codes required them sometimes for certain applications, such as an outlet in the floor. It’s possible sometimes they turned up just because someone was wiring an outlet and used what they had.

I think that was what happened in my friend’s case. My friend was confused because the outlet didn’t look like something he was used to seeing running at 115. And the outlet itself says it can run at either 125 or 250 VAC. Making matters worse, it initially had a wall plate that said it was DC. I think decades ago someone decided they needed an outlet, and that was what they had on hand or could get cheap, so they used it and didn’t care that it said it was something it wasn’t. Either scenario is completely on-brand for south St. Louis. Inspectors don’t put up with that today, but that wasn’t always true.

How to verify voltage on an unknown receptacle

To be safe, you can verify voltage with a multimeter, even an inexpensive one. Set the multimeter to its highest AC setting, then do what our parents always told us to never do. Insert one probe into one side of the outlet, and the other probe into the other side. Keep your hands on the insulated parts of the probe, of course. Then verify the multimeter reads around 115, as expected.

If the outlet reads 115VAC, you can either use it as an ungrounded 115VAC outlet, or replace it with a more common receptacle. If it reads closer to 220 or 230, you can replace it with a more standard 220VAC outlet. Keep in mind if you need to ground it, running new wiring to have a proper ground connection may be a better job for an electrician.

You may have heard that you have to replace the wiring if you do anything to the outlet. That may be true in some jurisdictions (that rumor came from somewhere), but it’s not true everywhere.There are times when it’s necessary to replace a worn-out outlet, and I can tell you at least where I live, it’s OK to replace a worn-out two-prong outlet with a new two-prong outlet. It’s even legal to put a GFCI in, as long as you label it as not truly being grounded.

Who was Harvey Hubbell?

Harvey Hubbell may not be a household name anymore, but for what it’s worth, he or his company invented most of the common electrical fixtures we use today. And the company is still in business today, even if the outlets you find in your local big box store probably are some other brand.

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