Six of the circuits in our 1950s vintage house are fed by 2-conductor fabric-covered cable, but they account for the majority of receptacles in the house. I’d like to get the receptacles grounded for convenience, so we can plug three-prong plugs into them, and for the safety of our electronics.
I’m in the process of getting bids from electricians to upgrade them, and the first one came in at $19,000, much more than I expected, because he apparently intends to replace all the wiring to switches and light fixtures as well as the outlets. As far as I’m concerned, this is unnecessary; the wires to switches and fixtures can stay ungrounded, I don’t see any practical advantage to rewiring them.
But I expect he’s going to tell me that it is required by code. Is that true? (We’re in Massachusetts, if that makes a difference.)
For new construction it is probably true, but for repairs/upgrades your wiring it isn’t. Fabric covered wiring does suck, maybe he’ll just tell you its best to remove as much of it as possible.
Please remember code varies by township and not just state. So it is extra hard to speak to code for anyone.
These days, most places require new installs to have grounded wires to everything. Anything within 6’ of water (sinks, tubs, etc.) will probably require GFCI.
We updated a rental house (built in the 50s) a few years ago. All outlets updated 3 prong but only a few where actually grounded per code. I thought “okay, it was wired with armored cable, just ground the outlet to the junction box and the cable grounds it back to the box”. No can do as a chunk of armored cable may have been replaced with plastic conduit breaking the ground and may be hidden behind a wall. To pass inspection either rewire the outlets or put GFI breakers in the breaker box. GFI breakers are expensive but cheaper than a rewire. The fixtures/switches did not need to be upgraded. The rental inspector gave the breaker box an odd look but all the outlets passed.
As stated by a6ka97, you can install a three-prong receptacle (NEMA 5-15R or 5-20R depending on circuit rating) when no ground is available as long as: 1) the receptacle is GFCI-protected, 2) local code doesn’t forbid it, and 3) a sticker that says “no equipment ground” is affixed to the receptacle.
As for #1, ensuring the receptacle is GFCI-protected can be achieved in three ways: a) the receptacle itself is a GFCI receptacle, b) the receptacle is down-stream from a GFCI receptacle, or c) the entire circuit is protected by a GFCI circuit breaker in the main panel. Option b) is usually the most cost-effective in terms of the cost of hardware, but it requires some sleuthing.
The inspector used his little tester on all the outlets.
An expensive learning experience for me and some advice for those buying an older house. Don’t assume that because the outlets have holes for 3 prongs that the outlets are grounded.
I’ve done this myself with 4 or 5 receptacles in our 1948 house. Getting it rewired and repiped are both projects we need to get done, though. We had the kitchen and basement remodeled, so those areas have grounded 3-prongs with new wiring now.
I thought most states and localities generally followed a standard national code. Is that not true?
I’m aware of this, and we have several properly labeled ungrounded GFCI outlets in the house already. But as I stated in the OP, in addition to the convenience of having three-prong outlets everywhere, one of the main reasons for this job is specifically for the protection of our electronics: computers, router, TV, etc. At the moment, grounding one or two outlets in the den would cover those specific items, but ideally I’d like to have at least one properly grounded outlet in the living room and our bedroom as well, to allow for different arrangements in the future. For a few of the old circuits, GFCI breakers would probably be sufficient.
So can anyone say for sure (or point me to resources that can help me determine) whether grounding outlets but leaving the wiring to switches and fixtures ungrounded is permitted by the national code? If it isn’t, my local code is probably not more lax.
Massachusetts currently follows the 2020 edition of NFPA 70, the National Electric Code, with about 20 pages of Massachusetts-specific amendments (google 527 CMR 12.00). Every municipality in the Commonwealth has to follow the same requirements.
How does that work? My probably too dangerous for my own good knowledge says that a GFCI is just that. If you have an outlet unprotected by grounding, then shouldn’t the circuit fail?
Also what good is it? It’s still ungrounded. Keep the two prong and rip the fat prong off. (Not that I recommend that, but protection-wise, what is the difference?)
Less than 1,500 sf. It’s a lot more than I expected, too. But as I said, he seems to want to replace most of the wiring inside the walls of the house, which is more than I wanted done.
I’m getting other bids. But the first company that came out (henceforth “company A”) wanted $600 just to come back and trace all the circuits to tell me what was needed and how much the actual job would cost. At least the $19,000 bidder (“company B”) opened up the main panel, determined that there were only six ungrounded circuits and which ones they were, without charging me.
Well, again, all disclaimers aside, but it seems like a job two handymen could do in three days. I would just spitball $2k in materials and double that for labor ($4k) so I would have guessed $6k. And the joints and wires are already there. Cut out the old box, two guys fish the new wire, put in a new box and new outlet and move on. New breakers where you need and even a new panel. I stand to be corrected, but that seems very pricey…like VERY excessively pricey.
Although I had no idea what the estimates might be, I would have been happy to pay around $4,000 to have the outlets grounded. We’ll see what the other companies say, and whether company B is willing to modify the scope of work to lower the total.
As it happens, although we are far from wealthy, our little house, which has been in my wife’s family since 1960, has an ocean view and is valued on Zillow at about $1.3 million. (My wife likes to say it’s $50,000 for the house and $1.25 million for the view.) The community is fairly affluent, and we’ve found that many workmen quote prices higher than we expected. We strongly suspect they assume everyone in this area is a millionaire.
While this is in no way intended as advice (I’m not an electrician and know nothing about electric codes) it does remind me of a little anecdote that is sort of amusing in light of the $19,000 estimate.
A great many years ago I was renting an old house that had no electrical grounding anywhere. It didn’t much matter except I really needed a grounded outlet in one room for my computer equipment and UPS. I simply replaced the old outlet with a three-prong type, and ran a ground wire down to the basement which I clamped to the copper water pipe. This probably violated code and best practices, but my little circuit checker indicated proper wiring and a good ground. The total cost for a length of single-conductor wire and hose clamp was probably about a dollar. The new outlet itself was probably a few bucks more.
Again, this is not intended as advice. I’m sure that electricians and knowledgeable DIY-ers will be able to point out a host of potential issues with my little fix, but it accomplished what I needed within the constraints I had at the time.
Let’s say a device with three-prong power plug is plugged into a three-prong receptacle. There is a ground fault within the device.
Scenario 1: The ground prong for the receptacle is tied to ground at the circuit breaker panel. A very large current will be created the instant the ground fault occurs. The circuit breaker will sense this very large current, and the circuit breaker will trip. The circuit and device are now de-energized and safe.
Scenario 2: The ground prong for the receptacle is not tied to ground at the circuit breaker panel. In fact, it’s not connected to anything. But the receptacle is GFCI-protected. In many cases, after the ground fault occurs, the device will continue to be energized, and will continue to work. Now let’s say you walk up to the device and touch it. We will also assume you are grounded. The GFCI will detect this and trip. The circuit and device are now deenergized and safe.
So while having a three-prong, ungrounded GFCI is “legal” in most areas, I am not a big fan it. Because often times, the device with the ground fault is sitting there fat, dumb, happy, and working, yet the metal chassis is at a dangerous voltage relative to earth ground. The protection system first requires you to touch it - and perhaps even experience a slight shock - before it deenergizes the circuit. Not ideal, obviously. And this assumes the GFCI is working. (Of course, there are some other scenarios where the GFCI will immediately deenergize the circuit when it detects a ground fault. This can occur if the chassis is somehow grounded another way, which is not guaranteed.)