Ungrounded Romex Wire

Wondering what is ungrounded romex and why should I be concerned with it? To understand the issue with ungrounded romex, we first need to understand what the ground wire does? (Note that the name ungrounded romex implies it has no ground) The ground wire is there for personal safety, it’s that simple. A good way to think about it is like this – Imagine you have a refrigerator that has a metal frame/body plugged into an ungrounded (2 prong) outlet with one of those 2 to 3 prong adapters (you know the ones!), and within that refrigerator the “hot” wire is touching the ground wire or frame of the fridge. The frame of the fridge would now be LIVE. Yes, it would have live potential, that if someone touched it while touching another appliance that has a ground, you would get a shock. Or if you touched a water source (sink) or standing on a concrete floor (basement) amongst other possibilities.

If you had the same exact situation (issue within fridge, hot touching ground within the appliance) but the circuit powering the fridge was GROUNDED, the circuit breaker would trip instead, preventing a potentially hazardous situation.

What is the chance of that happening? I remember when I was an apprentice my father got a call to house in Somerville. The tenants claimed that when they touched the fridge and range at the same time (they were side by side) they got a shock. Sure enough, when we got there my father took his electrical meter and measured the voltage between the frame of the fridge and range and got 120 volts. To further demonstrate this, he got a temp light bulb and socket, and touched the wires to the frames and the bulb lit up!! I’ll never forget that.

Now I’m not saying all this to scare anyone, as these are pretty rare situations. But it’s good to know why having no ground within your wiring is not good, and why all branch circuit wiring since 1962 has been mandated to have a ground wire within it.

How do you know if you have ungrounded romex wiring?

Good question! There are two main generations of it. One was used in the 1920’s, usually seen along side knob and tube wiring. I have inspected a few houses that were completely wired in this kind of very early ungrounded romex wire. This ungrounded romex wire had their individual conductors jacket wrapped in a cotton braid that had a tar substance smoothed over it for moisture protection. It’s a dark black cable as seen to the right.

You can see the ungrounded romex wire going into the light box (black cable). There is a BX wire also going into the same box on the right. It is very common to see both wiring types working together.

ungrounded BX wire

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The 2nd generator of ungrounded romex wire was used throughout the 1950’s. Typically if your house was built in the 1950’s you will have this type wire. This wire has a jacket that is also black. Below is a picture of the 1950’s ungrounded romex, it’s noticeably thinner than the first gen –

Picture coming soon!

It depends on what year your home was built. If it was built in the early 1900’s, I would be looking in your unfinished basement or attic for the thick dark black cables above. If your home was built in the 1950’s, the 2nd one is what I’d be looking for. Another thing to look for are 2 prong outlets. 2 prong outlets have no ground terminal and would have been original equipment on both of these wiring types.

Additional issue with ungrounded romex wire

Besides this kind of wiring having no ground, which is there for your safety. The other big issue with this kind of wiring is expansion. By the national electrical code, we can NOT extend off this wiring type. Meaning, if you have a 1950’s home and want to add one outlet in the bedroom, we cannot extend off an existing ungrounded outlet to add this, meaning a new properly grounded circuit from the electrical panel is needed.

Estimate Process

If your home was built in the 1950’s, it’s pretty simple. We offer a free in-home estimate where we will shut down ALL the visible ungrounded romex wiring in the electrical panel and walk through the home together, identifying all the outlets, lights, switches that are now OFF. When giving you your estimate we will list a “price per point” for changes. Meaning, if any points ( lights, switches, outlets) listed on your estimate DO NOT need to be replaced / rewired you will be due a credit (the price per point). If we find any other points that DO NEED to be replaced during installation, you will be charged the same amount per point. So it goes both ways and is perfectly transparent!

If your home was built in the early 1900’s and has the 1st generation of ungrounded romex, there is a good chance you have other types of early wiring as well. We often see early 1900 homes that have knob and tube wiring, BX wiring, and ungrounded romex all working together. If this sounds like your home, we can still offer the free in-home estimate, but a whole hole evaluation / mapping might make more sense.

If you are looking to replace ALL the old wiring, the free estimate is sensible. If you want to only replace one of the wiring types, for example: replace the ungrounded romex but maintain the BX wiring, an evaluation might be the better option.

Please give us a call today to discuss your options!

Ungrounded Romex Rewiring Process

Rewiring all different types of wiring works the same way. Some small holes will be necessary to fish the new wiring throughout the home. For more in-depth information about the rewiring process of homes please click here.

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