Very unusually to have missing grounds for a 1971 built house, I even called the realtor to verify the age. I though 1962 was the cut off year for missing equipment grounds ??
Evening, Sam. Hope this post finds you well.
The first requirement for grounded receptacles in residential construction dates back to 1951 when the NEC (National Electrical Code) required laundry areas to have grounded receptacles. Think of armored cable and metal junction boxes being bonded.
As for 3 slot outlets/receptacles. In 1969 Underwriters Laboratories mandated three-prong plugs on major appliances for safety.
Since 1962, the National Electrical Code has required three-prong outlets for all new homes.
Sam. How many outlets/receptacles ‘on a circuit’ were wired incorrectly or missing grounds? This may help in creating a narrative I use that may help you.
Looking forward to your reply.
The whole house had missing grounds, there was only 3 equipment grounds on the electrical panel bus bar.
Sam… why does it matter? are you concerned with calling it out? we’re in 2020 and we, today, know that 3 prong receptacles require a functional ground Few scenarios are possible as to how the house ended up this way, but why does it matter? it’s an old house… it has no grounds but 3 prong receptacles, that’s all we need to call it out If you were thinking of putting it was required when the house was built and or its electrical upgraded… I’d never do that because now you’re stepping into the code territory. This information won’t help the client in any way.
Can’t they simply replace with GFCI receptacles?
Yes,…and mark each ungrounded receptacle “NO EQUIPMENT GROUND”.
P.S. It looks, to me, like the service had circuits added, IMHO.
Yes, without a ground (in older houses) replacing 2 prong receptacle is only allowed if GFCI is used (and marked, as Larry mentioned). However, when adding new circuits you cannot just use GFCI… an EGC has to be supplied by the circuit.
Can a person even buy (new) an NM cable, in the 12/14 gauge, without a grounding conductor nowadays?
Not that I know of, nope. However, NM is not always used to run circuits.
Good point, Simon…
What type of cable was used for these circuits? Was it NM cable without an EGC or was AC cable?
Even if, the outlet should still test grounded, no? (if metal box was properly bonded)
Yes you’re correct it should be grounded via the AC cable jacket which can serve as the EGC. I was just curious as to the wiring method.
If they used proper AC, then the receptacles most likely would’ve had ground I bet they just swapped 2 to 3 prong. But hey! one never knows. Yes, would be helpful to see what the entire panel looked like.
Yes you are correct NM
A house built in 1971 should have NM cable with an EGC within the cable. Do you have a close up photo of the cables where they enter the panel?
No I no not, I pulled the outlet covers off and there were only 2 wires coming in.
I’m only asking because there was a time when EGC’s were first introduced in NM cables that guys pulled them outside of the box and connected them on the outside.
I agree just call it out and recommend evaluation by licensed contractor