So this ancient, ungrounded and live 20A twistlock relic is down my basement.
Can I safely update it, ground it and use it for pinball machines or do I have to rip out the feed all the way from the circuit breakers?
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Intriguing since most of my machines don’t use a grounded plug. The top is probably neutral and bottom is hot. Answer, I don’t know.
This might help
Quoted from jeffc:I would not trust anyone named electrocute on this matter
pasted_image (resized).jpegQuoted from jeffc:I would not trust anyone named electrocute on this matter
Greatest response ever
Quoted from embryonjohn:Greatest response ever
yeah, i got a charge out of that too.
As old as that looks, I would want to know the wire size feeding it. Also, if you have “modern” machines, they depend on ground, so make sure ground is really there if you add a three prong plug.
Nothing like the thrill of finding out your grounded receptacles are not grounded, and your knob and tube wiring is “protected” by a 20 amp breaker, and the wire can’t handle that many amps.
Quoted from Billc479:As old as that looks, I would want to know the wire size feeding it. Also, if you have “modern” machines, they depend on ground, so make sure ground is really there if you add a three prong plug.
Nothing like the thrill of finding out your grounded receptacles are not grounded, and your knob and tube wiring is “protected” by a 20 amp breaker, and the wire can’t handle that many amps.
Yeah, I was thinking the same. I believe they run a smaller gauge of wire vs. the standard 15A breaker run.
Quoted from vid1900:They still make those.
You could replace it with a regular 3-prong duplex, if there is a ground available inside the box.
Or you could install a GFCI, and it will still protect without the service ground
[quoted image]
I did not know that. I have a few outlets ungrounded and that would be an easy way to get some protection.
Quoted from embryonjohn:[quoted image]
...the hospital...the morgue...
Let's see a clear picture of whats inside the box behind the receptacle
Turn off power at breaker
remove cover plate
remove receptacle
light it up bright and show us some focused pics
Did you test it with your meter? Is it 120 or 240v ?
Quoted from embryonjohn:So this ancient, ungrounded and live 20A twistlock relic is down my basement.
Can I safely update it, ground it and use it for pinball machines or do I have to rip out the feed all the way from the circuit breakers?
[quoted image][quoted image]
The wire and breaker - not the outlet.. are really what bound what you can do. Gotta pull the outlet, look at the type and size of wire.. and the termination at the service panel.
Quoted from RyanStl:I did not know that. I have a few outlets ungrounded and that would be an easy way to get some protection.
Quoted from jeffc:I would not trust anyone named electrocute on this matter
Also Florida. 
Quoted from vid1900:Let's see a clear picture of whats inside the box behind the receptacle
Turn off power at breaker
remove cover plate
remove receptacle
light it up bright and show us some focused pics
Did you test it with your meter? Is it 120 or 240v ?
Will do
Quoted from RyanStl:I did not know that. I have a few outlets ungrounded and that would be an easy way to get some protection.
Quick FYI about a GFI
In a nut shell, a GFI simply monitors the delta of the current on hot line and the current on the neutral line. If everything is working correctly, the currents are the same (i.e. 1A on the hot coming in, 1A leaving on the neutral) and the GFI doesn't trip. If there's an imbalance (i.e. 1.005A coming in on the hot, and 1.000A leaving on the neutral), then that missing 5mA might be going thru you so it trips.
Don't know the actual trip point - I just tossed out some numbers for an example.
Quoted from mbwalker:I just tossed out some numbers for an example.
220, 221.... whatever it takes!
Quoted from JayDee:220, 221.... whatever it takes!
OK, I might as well look it up...
"A GFCI, by standards definition, must trip the circuit if a ground fault occurs with a maximum of 6mA of current loss to ground. GFCIs are typically considered personnel protection devices and the maximum 6mA trip level is set at a level to protect injury to people."
"Trip time is the amount of time it takes for the device to cut off the power to the line after sensing the appropriate amount of current loss to ground...are designed to trip in less than the UL/CSA/ANCE standard of 25mS. The shorter the trip time, the less chance of personal or equipment injury"
Quoted from mbwalker:OK, I might as well look it up
Mr Mom reference. I couldn’t resist 
Quoted from JayDee:Mr Mom reference. I couldn’t resist
Didn't realize that. Great, now I have to look that up too! 
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