Floating ground ?

[radio nut]

My wife and I just moved out of a crappy apartment and into a house(rental).
When talking with the landlord he told me that the house was built in 1925 and that currently the wiring while it has a circuit breaker installed it is only a two wire set-up.
One wire is hot and the other neutral, and does not have the third wire for ground.
Talking with a electronics tech. he said that my house could very well have a floating ground.
Well, how do I tell if it does have a floating ground and what would it affect?

[maxhifi]

I am not sure what he meant by that. The utility feed will certainly have the neutral and ground bonded together at both the transformer and the service entrance at
The house. Check voltage between hot and a water pipe or radiator pipe to check it, should be about 120 to ground. If you get any other value either the pipe
Isn't grounded or there's a problem with your electrical system.

[dieseljeep]

Originally Posted by maxhifi

I am not sure what he meant by that. The utility feed will certainly have the neutral and ground bonded together at both the transformer and the service entrance at
The house. Check voltage between hot and a water pipe or radiator pipe to check it, should be about 120 to ground. If you get any other value either the pipe
Isn't grounded or there's a problem with your electrical system.

Get the electric utility to come and check it out.
The owner might be mistaken about the service entrance. I don't know of any homes that still have a two wire 120 volt service. They only were good for 30 amps, max.
The 1959 code required a minimum 120/240 volt, 100 amp, three wire service, for residential applications. It didn't make any difference, how many circuits were used. I've seen 100 amp services, that only had, two 15 amp 120 volt branch circuits. They owner did it to satisfy the insurance company.

[earlyfilm]

Originally Posted by radio nut

Talking with a electronics tech. he said that my house could very well have a floating ground.

He means that some receptacles might be reversed.

With that said, unless you were talking about commercial use, there were no grounded receptacles back then, so any polarized receptacles in the house are modern, and they may be wired wrong.

Back in the day, most electricians did not bother to mark which wire was hot and which was ground, as you could put in the plug either way.

To the best of my knowledge, if the house was built to code, and no new outlets were needed, you could leave in place any wiring that met code when the house was built. The laws governing this vary from community-to-community.

(Floating ground can also refer to 120 taken off a three phase circuit, where neither side of the two wires is grounded. This happened in some early buildings, that had phase heavy motors and someone goofed while adding a circuit. I've only seen this in older commercial buildings, not in private homes.)

James

[dieseljeep]

Originally Posted by earlyfilm

He means that some receptacles might be reversed.

With that said, unless you were talking about commercial use, there were no grounded receptacles back then, so any polarized receptacles in the house are modern, and they may be wired wrong.

Back in the day, most electricians did not bother to mark which wire was hot and which was ground, as you could put in the plug either way.

To the best of my knowledge, if the house was built to code, and no new outlets were needed, you could leave in place any wiring that met code when the house was built. The laws governing this vary from community-to-community.

(Floating ground can also refer to 120 taken off a three phase circuit, where neither side of the two wires is grounded. This happened in some early buildings, that had three wire heavy motors and someone goofed while adding a circuit. I've only seen this in older commercial buildings, not in private homes.)

James

Unless I've seen the wiring done in the home, it's hard to advise anyone.
I re-read the O/P and the owner was probably referring to the receptacles.
They were probably replaced with the newer grounding type. If the home was wired with the old style B/X cable, there might be, somewhat of a ground, but not a perfect one. If you meter the hot wire to the box, you'll get a reading.
If the home has knob and tube wiring or the old style romex without the ground wire and the receptacles, were replaced with grounding ones, it's a code violation.
Buy one of those simple, three light receptacle testers and it'll will indicate if the receptacle is wired properly.

[radio nut]

I will check the outlets with a tester this weekend. If not up to code...could the two wired outlets cause issues with my electronics?

[Username1]

If the home has knob and tube wiring .................

I would worry more about this little bit of funky wiring, and the possibility of
FIRE and less about your electronics.....

And looking at my own house, and some of the stories on VK about house wiring
It does not matter what the code is, what matters is WTF they actually did....
And if the stuff made back then has any surprises yet to show themselves
because you may put a greater demand on them than what previous owners
may have......

.

[oldtvsandtoy]

1st you can not have a floating ground, you have a floating neutral. In your panel a ground and neutral can be one of the same, in your house they can not. In the old days your chassis was use as a ground. So if you plug your cord in wrong your chassis would be hot, and you could get zapped. This has happen and people did get killed. That is why we use the 3 wire system today. Now with that said here in Michigan a house must be brought up to code to rent it out. 3 wire systems are code in a home. You need to call city hall to see what code in in Ohio. Most likely it's a 3 wire system, they will make the landlord bring the house up to code. Or he will not be able to rent it out. You should check it out.

[oldtvsandtoy]

No you can have more then 30a on a two wire system. You just need to use bigger wire. A dryer can run on two wire 40a and a stove on two wire 60a

Originally Posted by dieseljeep

Get the electric utility to come and check it out.
The owner might be mistaken about the service entrance. I don't know of any homes that still have a two wire 120 volt service. They only were good for 30 amps, max.
The 1959 code required a minimum 120/240 volt, 100 amp, three wire service, for residential applications. It didn't make any difference, how many circuits were used. I've seen 100 amp services, that only had, two 15 amp 120 volt branch circuits. They owner did it to satisfy the insurance company.

[Kevin Kuehn]

What scares me more than the old two wire system's, is the modern code approved twisted(wire nut) connections, and those crazy push in terminals on the back of duplex receptacles.

[maxhifi]

I think there is some confusion here. "two wire system" is being interpreted two ways, both of which are correct.

1. A "three wire service", is a 120/240V service. If you have a circuit breaker panel this is probably what you have. If you have an electric stove or dryer, this is definitely what you have. The "two wire service" which was 120V only, was a very simple service basically for lighting loads only, and it is very unlikely such a service would still be in existence. I haven't seen one since the 1980s and that was at a house which had been continuously occupied since the late 1930s... finding a two wire 120V service on a house these days is looking for a real antique.

2. "two wire receptacles" means receptacles without a third (grounding) prong. As previously mentioned, if someone at some time replaced the original two prong receptacles with three prong receptacles (as these are more commonly available), the third prong is connected to nothing and thus "floating".

I would imagine your friend is talking about scenario 2, so what to do about it?

1. With any "two prong" electronics this is an absolute non-issue

2. If you must, you can use a GFCI to connect three prong loads, it will detect any current to ground and perform the same job as a ground connection. The Canadian Electrical Code permits a GFCI to be used as a substitute for a ground connection in existing two wire installations - I am not sure if the NEC does or not, but it's a method to improve safety.

3. Add a ground connection to specific existing outlet. Get an appropriate length of #14 XLPE wire, and connect it from the third prong of the specific outlet being grounded back to a solid ground, such as the electrical panel enclosure, or a copper water pipe.

About wire nuts - my house was built in 1962 and all the "wire nuts" are just fine... wire nuts are fine anywhere except where there's vibration, if installed correctly. Push in terminals on receptacles though are just crap, I can't believe they ever got a UL/CSA approval

[earlyfilm]

Originally Posted by maxhifi

3. Add a ground connection to specific existing outlet. Get an appropriate length of #14 XLPE wire, and connect it from the third prong of the specific outlet being grounded back to a solid ground, such as the electrical panel enclosure, or a copper water pipe.

Some locations require a grounding wire at the utility box and nowhere else. I got in a fight with the inspector in Memphis, because I grounded our washer and dryer to the copper cold water pipe instead of to the central ground. (Our washer and dryer were in an unheated, unfinished, concrete-floor utility room outside of the back of our house.) I did this because if something fails and the ground wire becomes hot and I wanted no possibility for a shock in this potentially wet area.

I then suggested to the inspector that I tie both together, and was told specifically that it was not permitted.

James

[wa2ise]

Originally Posted by maxhifi

...The "two wire service" which was 120V only, was a very simple service basically for lighting loads only, and it is very unlikely such a service would still be in existence. I haven't seen one since the 1980s and that was at a house which had been continuously occupied since the late 1930s... finding a two wire 120V service on a house these days is looking for a real antique. ...

Push in terminals on receptacles though are just crap, I can't believe they ever got a UL/CSA approval

My grandma's house, in 1984, had that 2 wire service. POCO cones into the basement, thru a 30A screw in fuse, then the meter, then to a pair of 15A fuses, and the neutral also had fuses, we used 30A fuses there, so the hot side 15A fuses would be the ones to blow. If we wanted to, we could have easily grabbed unmetered power at that first 30A fuse. But we didn't.

As for the push in terminals, I've heard electricians call them "Push and pray".

[maxhifi]

Originally Posted by wa2ise

My grandma's house, in 1984, had that 2 wire service. POCO cones into the basement, thru a 30A screw in fuse, then the meter, then to a pair of 15A fuses, and the neutral also had fuses, we used 30A fuses there, so the hot side 15A fuses would be the ones to blow. If we wanted to, we could have easily grabbed unmetered power at that first 30A fuse. But we didn't.

As for the push in terminals, I've heard electricians call them "Push and pray".

I am assuming 1894 - that's cool, my great grandparents house had that sort of a set up too, that's why they had a gas range and gas dryer.

[maxhifi]

Originally Posted by earlyfilm

Some locations require a grounding wire at the utility box and nowhere else. I got in a fight with the inspector in Memphis, because I grounded our washer and dryer to the copper cold water pipe instead of to the central ground. (Our washer and dryer were in an unheated, unfinished, concrete-floor utility room outside of the back of our house.) I did this because if something fails and the ground wire becomes hot and I wanted no possibility for a shock in this potentially wet area.

I then suggested to the inspector that I tie both together, and was told specifically that it was not permitted.

James

Yes, if you ground at more than one point you might create a ground loop, and get circulating currents. I said to ground to a pipe because realistically, it may be totally impractical to run a wire all the way back to the panel and there could be a water or radiator pipe staring you in the face. Of course I am assuming your water pipes are all metal and are grounded too, but given the age of the house it's probably a reasonable assumption.

Electrical code is designed in such a way as to be fool proof, but it is far from the only way to make something safe and reliable. Of course I am making the assumption that the pipe is a good ground, but it's not hard to verify if it is. Look at how wiring is done in Europe... much of it would NEVER pass inspection in north America but you don't hear scary statistics about electrical fires and electrocutions in Europe.