Author Topic: One of my wall outlets seems to not be grounded?  (Read 15097 times)

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Offline IanB

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Re: One of my wall outlets seems to not be grounded?
« Reply #25 on: March 22, 2014, 03:04:10 am »
Look closely, there is a small jumper that juts out a bit that electrically ties together those two screws.  They're intended to be broken off to isolate the top and bottom receptacles in case you want to feed them with separate circuits or have one on a switch.

Yeah, I want to ask about that.

"Just break off the tab. Put a screw driver in the slot and wiggle it back and forth and the tab will pop right off."

Yeah, right. In your dreams. Put a screwdriver in the slot and try to wiggle it and the slot will break. Try to grab the tab with pliers and there is not enough room to grasp it or wiggle it.

I'd like to know what mastermind came up with that design, and how exactly they think it is supposed to work? Am I missing some clever electrician's trick? Because I end up resorting to a Dremel and a cutting wheel  ???
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #26 on: March 22, 2014, 03:22:16 am »
Pair of Klein's (lineman's pliers).  One jaw on the back, one on the tab.  Squeeze.  It won't break, but it bends.  Then, put one jaw on the front and one on the tab.  Squeeze.  Usually comes off but sometimes needs another squeeze or two.  Just keep alternating the direction you squeeze the tab and let metal fatigue do the rest.
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Offline pickle9000

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Re: One of my wall outlets seems to not be grounded?
« Reply #27 on: March 22, 2014, 04:13:52 am »
In Canada it's perfectly legal to wire your own home provided you have a plan and get it inspected by the municipality (as far as I'm aware). You can get a simplified code book at the local building supply (Electrical Code Simplified House Wiring Guide) , it's province specific and it has all rules. The book is about 150 pages and is well diagrammed, it's updated whenever the code changes. I would recommend reading it even if you just want to understand what is in your walls.

The receptacles you buy are well marked with wire strip lengths and colour coded screws (silver=white bronze=black and green is ground). Screws are Robertson (square drive) and slotted. The red handled Roberson driver is used for rough in and green handle for electrical connections (except in a breaker panel). For anyone that has not used Roberson screws they allow the screw to stay on the driver without assistance. Similar to a tight fitting cap head, really nice to use. 

Even though it's legal to wire your own home most people use a professional, repairs are common enough.

15 amp circuits are the norm.
 
 

Offline Clear as mud

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Re: One of my wall outlets seems to not be grounded?
« Reply #28 on: March 22, 2014, 02:39:49 pm »
"Just break off the tab. Put a screw driver in the slot and wiggle it back and forth and the tab will pop right off."

Yeah, right. In your dreams. Put a screwdriver in the slot and try to wiggle it and the slot will break. Try to grab the tab with pliers and there is not enough room to grasp it or wiggle it.

I'd like to know what mastermind came up with that design, and how exactly they think it is supposed to work? Am I missing some clever electrician's trick? Because I end up resorting to a Dremel and a cutting wheel  ???

No, it really is easy with just a screwdriver, if the screwdriver is small enough to fit in the little space.  The trick is to use metal fatigue to your advantage, and just keep bending it back and forth until it breaks off.  It only takes about 4 or 5 times going back and forth.  You can use the same method to break a piece of wire with your bare hands, with no tools at all.  Just take the wire and quickly bend it back and forth until it breaks.  Sometimes it gets too hot to hold before it breaks, though.  It helps to go quickly.  Also in the case of the metal tab on the receptacle, you want to bend back and forth about once per second, not too slowly.  Assertively, but not forcefully enough to break anything (besides the metal tab, of course).

But I'm not sure why we're talking about breaking the metal tab, with regard to the original post.  It's possible that the red wire is a switched hot that could feed half of the receptacle, but without knowing for sure where the cable comes from, we can't just assume that.  Some testing or tracing of wires is required.
 

Offline Clear as mud

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Re: One of my wall outlets seems to not be grounded?
« Reply #29 on: March 22, 2014, 03:05:19 pm »
That outlet is a mess.
It has a big four conductor wire running into the box and only the black and white are used. No ground wire at all.
I'm guessing my father did this back in the 80's.

Before modifying it in any way at all, I would trace that cable to where it comes from.  My guess is that the other end also has only the black and white connected.  To add a ground, you'll have to connect the ground at both ends.  That's not too hard, assuming everything else is grounded.  But if the box where that cable comes from is also not grounded, you'll have to connect ground there as well, and so on back to the main panel.
From your description, it appears to me as if the outlet was added by someone else after most of the wiring was already done.  It may have been your father, as you said.  But whoever added it thought the ground was not important.  Possibly they thought that outlet would only be used for a lamp, which doesn't even use the equipment ground.  Or, possibly they thought grounded outlets were a new-fangled thing and not worth the effort to run a third conductor, since for so many years nothing had that extra ground wire.  I've seen whole houses wired that way, with every ground wire cut off in every box.  In fact, I've rewired a whole house that was wired that way, re-using each wire in a place where a slightly shorter wire was required, so that it would be long enough to connect the grounds which were originally cut too short to connect.

If the red wire is not being used for anything, you could cap it off at each end, or you could replace the whole cable with one with only two insulated conductors, and re-use the 3 conductor one someplace else where you need the extra conductor.  That looks like 14-gauge wire to me, so it should be relatively cheap and easy to work with, but if the circuit is 20 amps, it should be 12-gauge instead of 14.  Truthfully, you'll probably be OK leaving it at 14-gauge even if it is a 20 amp circuit.  I've seen whole houses wired with 14 AWG, where the original 10 or 15 amp fuses had all been replaced with 30-amp fuses, and the wiring operated for years like that without causing a fire.  But you have to be aware that the probability for a fire is higher than if you used the correct size wire, and also that after such a fire, your insurance company may not cover the loss if they are aware that you were aware the wire size was too small.

20-Amp circuits with 12 AWG wire are the norm around here (Oklahoma), but I'm well aware that in a lot of other areas, 15-Amp are more common because of the thinner and cheaper wire required.
« Last Edit: March 22, 2014, 03:11:29 pm by Clear as mud »
 

Offline dentakuTopic starter

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Re: One of my wall outlets seems to not be grounded?
« Reply #30 on: March 22, 2014, 03:06:19 pm »
Looks like your standard 3 conductor romex with ground.  Dead end circuit.  Easy fix.  Use a voltage tester first.  Ensure that you have 120v between the bare wire and the black one.
0v between bare and white
Wouldn't hurt to check the voltage between white and red too.  That red may or may not be connected to anything.  But, I'll bet there's a switch in the room that controls that red wire.  Someone wanted both receptacles (top and bottom) hot all the time and just cut the red wire flush and replaced the outlet.

Be careful with the red wire.... it's possible (though not likely) there is 120v on it from the other leg which means it could be live, AND 240vac to the black one.  My money is on a switch somewhere.

Yup, 120V between black and the bare wire, 0V between white and the bare one, nothing between white and red.

I found a better, more modern receptacle downstairs so I guess tomorrow I'll switch off the breaker that leads to it and replace the whole thing.

The receptacle seems to lead to a junction box that branches off to a bunch of other places including the water pump and the furnace. I then traced the wire going INTO this box and it leads to the circuit breaker section that's labeled pump and furnace.
Lots of the outlets in the house are connected to breakers named PLUGS including the other two outlets in this room but this one seems to have just been added later so it shares with other stuff.

By the way, why would you connect the ground wire to the box anyway?
The junction box this wire goes to has the bare ground wire screwed into the box though.

Yes, grounding the box is code, but it's really just customary on anything to ground anything metal that isn't directly electrified.  The reason is because a chafed wire, broken down insulation, a gum wrapper in the wrong place or anything could inadvertently make contact with a hot wire (see that screw on the receptacle where the black wire goes?  Pretty close to the box, eh?) and the metal box. Then you'd have a box that's exposed for anyone to touch and "zap".  A lot of people don't know this, but the frame of the receptacle is in electrical contact with the box.  And the trim screw that holds on the plate screws into the frame.  If the box gets electrified and it's not grounded, anyone who touches that screw with bare feet on tile could conceivably be killed.

There's also a less nefarious reason... If the neutral wire touches the box, or even if the box is mounted to a metal conduit that goes under ground, there may be a potential difference (voltage) between the box and the ground you're standing on.  I've gotten mild shocks that way.  Seen the same thing with a metal kitchen sink before too.

If you can't ground the box easily, if you have a "self-grounding" receptacle, it will act as a ground for the box.  It's no longer legal, by code, but it was legal up to about 15 maybe 20 years ago.  Ground it if you can. 

Listen to the warnings about the red wire.  They are valid.  Though, stripping the wire and taping are overkill.  The wire nut is sufficient.  Whatever you do, don't cut it flush with the sheathing.  Code says a minimum of 6" needs to stick out of the box.  That "rule" is nearly ALWAYS violated by electricians because it isn't always practical.  Just leave as close to that as you can and you're good.

One more thing... that receptacle you're going to replace it with... if it's used, make sure you get the black and white on the right screw black is on the right, white is on the left as you're facing it with the ground jack down.   Also, you will see two screws for the black and two for the white.  Look closely, there is a small jumper that juts out a bit that electrically ties together those two screws.  They're intended to be broken off to isolate the top and bottom receptacles in case you want to feed them with separate circuits or have one on a switch.  Make sure the jumpers are there or else one receptacle will be dead.  Of course, you can jump it with a piece of copper wire.  14awg for 15A circuit.  12awg for 20A.

I hope I'm not being too presumptuous by volunteering so much info?

Yesterday I watched some videos on how to wire an outlet so I could visualise everything you said. It's always nice to have good information so thanks.
 

Offline dentakuTopic starter

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Re: One of my wall outlets seems to not be grounded?
« Reply #31 on: March 22, 2014, 03:12:48 pm »
If you can't ground the box easily, if you have a "self-grounding" receptacle, it will act as a ground for the box.  It's no longer legal, by code, but it was legal up to about 15 maybe 20 years ago.  Ground it if you can.

But the frame of the receptacle is also directly connected to the ground wire (if the ground wire is attached to ground screw on the receptacle). So ultimately all metal parts are connected and grounded. I know it may not be to code, but I don't feel too bad about grounding the receptacle and letting the box share the same ground. Sometimes it's fiddly to make lots of pigtails.

Yup, the receptacle I'm going to replace the ugly old brown one with has the green ground screw connected to the tab that screws into the box so it'll be in contact with the box anyway.
« Last Edit: March 22, 2014, 03:19:50 pm by dentaku »
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #32 on: March 22, 2014, 03:15:01 pm »
It was a reasonable guess... 3 conductor costs almost twice as much as two conductor.  It's a dead end circuit, meaning the red wire was most likely intended to feed something in THAT box.  Mentioning something as a possible or likely doesn't imply it is at the exclusion of all else.  In the end, the red wire is irrelevant.

Why is "some testing or tracing of wires required?"  The red wire wasn't connected to anything and the OP isn't planning on using it for anything.  Whether it's hot, neutral, grounded or not connected is irrelevant.   Put a wire nut on it and call it a day.   Someone asked about the red wire.  I simply offered a plausible explanation. 
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Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #33 on: March 22, 2014, 03:34:21 pm »
If you can't ground the box easily, if you have a "self-grounding" receptacle, it will act as a ground for the box.  It's no longer legal, by code, but it was legal up to about 15 maybe 20 years ago.  Ground it if you can.

But the frame of the receptacle is also directly connected to the ground wire (if the ground wire is attached to ground screw on the receptacle). So ultimately all metal parts are connected and grounded. I know it may not be to code, but I don't feel too bad about grounding the receptacle and letting the box share the same ground. Sometimes it's fiddly to make lots of pigtails.

Yup, the receptacle I'm going to replace the ugly old brown one with has the green ground screw connected to the tab that screws into the box anyway so it'll be in contact with the box anyway.

Sounds like you have it under control.  Isn't the internet a wonderful thing?  I mean videos and everything!  I suppose it's not real crucial, but be advised, as far as I can remember, the green screw has always been mechanically connected to the "yoke" or receptacle frame, but THAT is NOT what makes it "self-grounding."  If you look behind one of the "ears," the part that the 6-32 screw goes through to attach the receptacle to the wall, you should see a little brass sheet metal clip that makes constant contact between the screw and the yoke.  THIS is what makes it self-grounding (other implementations are possible).

Look at it this way, a good ground can only occur if you have constant force at every junction ensuring contact all the time.  Typically, the receptacle is supported by drywall, not the box.  The screws make good contact with the box through the thread, but the receptacle is essentially "floating" free between the box and screw head.  Before self-grounding receptacles, it was possible to apply a little force on the outlet, such as when plugging in a lamp, and the drywall would give enough to break contact between the yoke and the screw.  Meaning, the ground could potentially be lost.

Without that clip, I would urge you to make a proper mechanical connection.  The romex has a ground.  The box should be firmly grounded.  So should the receptacle be grounded.  I probably wouldn't be quite so concerned about cutting corners on this if it weren't for the fact you have test equipment plugged into it. 

Just to be clear modern code requires a ground wire firmly linking every box, outlet and switch, regardless of self-grounding devices.  As I said, I might relax on this point in my own home because it wasn't that long ago the code said it was okay to rely on self-grounding devices, but I would insist on either self-grounding OR wire and screw connection.
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Offline Clear as mud

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Re: One of my wall outlets seems to not be grounded?
« Reply #34 on: March 22, 2014, 03:59:08 pm »
Why is "some testing or tracing of wires required?"  The red wire wasn't connected to anything and the OP isn't planning on using it for anything.  Whether it's hot, neutral, grounded or not connected is irrelevant.   Put a wire nut on it and call it a day.   Someone asked about the red wire.  I simply offered a plausible explanation.

It would indeed be nice if the red wire were connected to a switch on the other end, so that's why I would attempt to test or trace to verify.  Because if so, then you can make use of that feature and split the outlet into a switched and non-switched half instead of simply capping it off.
The other reason some further testing is required is that the initial test that you suggested does not verify that the clipped-short ground wire is connected to anything at all at the other end.  You said to test voltage between the white and bare and make sure that it's zero volts.  A multimeter will read zero volts on that test if both are connected to ground back at the main panel as they should be, but it would also read zero volts if the other end of the wire were simply cut off, as this end is, which I thought was a more likely explanation than that the red wire is switched.  One reason I thought that was more likely is that both wires are cut off.  If they had simply had one electrician do the rough-in and another do the final installation, maybe they would cut off the red wire, not knowing that it was a switched hot.  But they still would have connected the ground.  The fact that both wires are cut off strongly suggests that this is a DIY repair and they simply only used two wires, which would also suggest that the other end of the cable may be done the same way.
I think in a later post you suggested that the ground wire should indeed be tested for good ground, but you didn't say how to do it.  A better way than verifying that white-to-ground is zero volts, would be to verify that black-to-ground is 120 volts.  It still doesn't tell you whether it might have a weak connection, but it at least tells you it is connected.
 

Offline pickle9000

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Re: One of my wall outlets seems to not be grounded?
« Reply #35 on: March 22, 2014, 05:02:11 pm »
I would agree that the outlet looks like a handyman special. It would be nice to know if there is a switch on the red wire but as long as it is in the box and capped it's in code. The problem with this sort of stuff is that you can't see inside the wall. It's entirely possible this is an extension just tagged in, no box just tape and wires. The only way to tell is to open the wall or scope (endoscope) it. I had a conversation with an inspector (many years ago) and his opinion was this. If the outlet wiring is questionable cap it off / lock it out and put a blank plate on it or verify it, then put in a new outlet a couple feet away. If you are unable, do not alter or tie into to the circuit. The follow up was even a professional makes mistakes, the code is such that it encourages failures to happen in electrical boxes. Always have concern for the next person doing work on the system. 

 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #36 on: March 22, 2014, 05:16:41 pm »
@clear as mud... Man, you assume an awful lot.

You assume he'd want a half switched outlet.  He made no indication.  You assume I was testing the ground for connection.  I wasn't.  I was testing to make sure the damn thing wasn't hot and THAT's why it wasn't connected in the first place.  You assume that bare wire wasn't hot.  I didn't.  You know what they say about assuming... when it comes to electricity, it can fry your ass.  The way it was wired doesn't "suggest" it wasn't done by an electrician... it WASN'T... period.  Never assume a bare wire is safe to touch. 

You suggest testing the bare wire to hot... THAT's obvious.  Especially, on a forum dedicated to electron-headed nerds like us all.  If I say test the bare for ground, I have faith he'd know how to do that OR he'd ask.  How many other people here suggested that bare wire might be hot?  What if it had been? 
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Offline dentakuTopic starter

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Re: One of my wall outlets seems to not be grounded?
« Reply #37 on: March 22, 2014, 11:58:20 pm »
I switched off the circuit breaker that leads to this outlet, checked it and it was dead.
I removed the ugly old brown one and replaced it with the better looking white one, stripped back the wire, cut them all to the same length, capped the uesless red one that's connected to nothing at both ends, the connected the three wires.

This wire is rather big gauge and ridiculously stiff to work with.

Now my new power strip doesn't complain that it's not grounded anymore.
 

Offline IanB

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Re: One of my wall outlets seems to not be grounded?
« Reply #38 on: March 23, 2014, 12:00:21 am »
This wire is rather big gauge and ridiculously stiff to work with.

True, dat. 12 gauge wire is surprisingly more painful to deal with than 14 gauge wire.
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #39 on: March 23, 2014, 12:10:32 am »
Yay!  Bravo Dentaku.  Bravo  :clap: :clap:

Well done.
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Offline dentakuTopic starter

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Re: One of my wall outlets seems to not be grounded?
« Reply #40 on: March 23, 2014, 12:48:02 am »
My father said that he put that outlet in himself which explains why it's a piece of recycled 12 gauge wire with an extra conductor that probably came from a fish processing plant of some sort.
I find it strange that the ground wire actually was connected to the box on the junction box it comes from downstairs :)
 

Offline IanB

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Re: One of my wall outlets seems to not be grounded?
« Reply #41 on: March 23, 2014, 12:57:19 am »
I find it strange that the ground wire actually was connected to the box on the junction box it comes from downstairs :)

Take a look at all the devices you own with mains plugs. Count how many of them have three pin plugs. In America, doesn't it seem like a ground connection is an "optional extra"?
 

Offline dentakuTopic starter

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Re: One of my wall outlets seems to not be grounded?
« Reply #42 on: March 23, 2014, 01:28:59 am »
I find it strange that the ground wire actually was connected to the box on the junction box it comes from downstairs :)

Take a look at all the devices you own with mains plugs. Count how many of them have three pin plugs. In America, doesn't it seem like a ground connection is an "optional extra"?

Other than laptop "power bricks" I've never seen a wallwart/plugpack with a ground pin.
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #43 on: March 23, 2014, 01:37:20 am »
Or table lamps or lots of things.  There's no reason to ground something that has no metal parts exposed but the prongs.  What would you ground?  Plastic?  Ceramic or glass (in the case of table lamps).
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Offline nihilism

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Re: One of my wall outlets seems to not be grounded?
« Reply #44 on: March 23, 2014, 01:40:03 am »
I find it strange that the ground wire actually was connected to the box on the junction box it comes from downstairs :)

Take a look at all the devices you own with mains plugs. Count how many of them have three pin plugs. In America, doesn't it seem like a ground connection is an "optional extra"?

Regardless of the lack of use of the ground by many appliances, as mentioned before in this thread, you still need the box and any metal on the outlet grounded, in case an accidental short is made between that metal and an active conductor. Better to have a tripped circuit breaker, rcd (or gfi? as you guys call them) or blown fuse than an electrified human.

No offense intended, but electrical installations in USA and Canada scare me. I think it is better here where only licensed electricians can do electrical work, it at least discourages people that don't know what they're doing from attempting electrical work. And you guys really just twist mains wiring together and use those wire nut things?? Just asking for a high resistance connection to develop, which can quite easily cause a fire, especially at the higher currents on a 110v system.
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #45 on: March 23, 2014, 01:49:55 am »
There's nothing wrong with wire nuts.  It's all in how they're used.  The wires are required to make a good mechanical connection independent of the wire nut.  In other words, the wires shall be twisted together in such a manner that they cannot pull apart without untwisting.  Then the wirenut is only intended to act as a cap to insulate the bare wires and prevent the wires from untwisting.  These things have been around forever and have an incredibly safe record.  Your fears about them are wholly unfounded.
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Online Monkeh

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Re: One of my wall outlets seems to not be grounded?
« Reply #46 on: March 23, 2014, 03:32:04 am »
Rest of us did away with damaging solid conductors with twisting years ago..

Not to mention the amusingly exposed terminals and wire loop connections.
 

Offline chipwitch

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Re: One of my wall outlets seems to not be grounded?
« Reply #47 on: March 23, 2014, 04:45:38 am »
That is so cute. Maybe if you blokes used a sensible voltage for powering your light bulbs, you'd find twisted wires more than sufficient a connection.   :-DD
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Online Monkeh

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Re: One of my wall outlets seems to not be grounded?
« Reply #48 on: March 23, 2014, 04:46:46 am »
That is so cute. Maybe if you blokes used a sensible voltage for powering your light bulbs, you'd find twisted wires more than sufficient a connection.   :-DD

Sorry, you've got it backwards, you're the one with twice the current to handle for no gain.
 

Offline VK5RC

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Re: One of my wall outlets seems to not be grounded?
« Reply #49 on: March 23, 2014, 05:30:36 am »
I also have to add that I think 230V is prob also 'safer' , at that voltage you tend to get less ventricular fibrillation induced.
We do have the switches the wrong way around though, up should be on, so you can switch off faster.
Whoah! Watch where that landed we might need it later.
 


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