Advice – US compared to EU 220v

[ducati_EL34]

I'm not going to argue with you about it. If you want a hot chassis, go for it.

Thanks. I already have one.

 

[gadget73]

The neutral will not go to the chassis. The only thing going to the chassis is the ground. An ohm meter will confirm this.

 

[WaynerN]

Interesting point
I hadn't really considered it from that point of view.
From a functional stand point it should work fine.
If the chassis is grounded , it's like any other 220v device.

Yes, it will work, but one leg of the voltage is not fused. Your call. You can always fuse both sides to be safe. The first thing the wires coming into the chassis should see is the fuse, then off to the switch, which now should be a double throw and you should disconnect both lines (not the ground).

 

[Dingman]

The neutral will not go to the chassis. The only thing going to the chassis is the ground. An ohm meter will confirm this.

You are correct.
However, In the USA, both the neutral and the grounds are bonded together at the distribution panel.
If a person makes the previously neutral a hot leg and apply power, maybe it all would be fine. But if the neutral and ground ever touch each other in that unit, things will happen (maybe just a breaker trip).
It just sounds like a really bad idea, when there are other, not expensive but safe, solutions.

 

[ducati_EL34]

You are correct.
However, In the USA, both the neutral and the grounds are bonded together at the distribution panel.
If a person makes the previously neutral a hot leg and apply power, maybe it all would be fine. But if the neutral and ground ever touch each other in that unit, things will happen (maybe just a breaker trip).
It just sounds like a really bad idea, when there are other, not expensive but safe, solutions.

Warning: Dead Horse beating in progress!

No one is making a "previous neutral", hot. You would be taking two hot legs from the panel (via an outlet, like an AC clothes dryer), the only difference is you are powering the primary of a transformer.

 

[Sandstrom]

Sorry Guys, didn't mean to inspire a heated 'debate' here but this difference of opinion is exactly what I have found anywhere I have read on this subject. It's a very interesting issue to me. I have decided to take the 'safer' road here but it would seem that this is possibly a viable scenario, albeit with some modifications necessary to ensure the best possible safety.

I do really appreciate everyone's opinion on this. You folks aren't required to way in on something that has possible personal or equipment risks for others and for your willingness to state your personal opinion I thank you all very much!

 

[ducati_EL34]

Sorry Guys, didn't mean to inspire a heated 'debate' here but this difference of opinion is exactly what I have found anywhere I have read on this subject. It's a very interesting issue to me. I have decided to take the 'safer' road here but it would seem that this is possibly a viable scenario, albeit with some modifications necessary to ensure the best possible safety.

I do really appreciate everyone's opinion on this. You folks aren't required to way in on something that has possible personal or equipment risks for others and for your willingness to state your personal opinion I thank you all very much!

Well I would not call it a debate. How about a good discussion? I just want to know why this amp is any different than a stove top, or other 220v electrical appliance.

 

[Sandstrom]

Well I would not call it a debate. How about a good discussion? I just want to know why this amp is any different than a stove top, or other 220v electrical appliance.

Me too! What spins in my head is how are these US devices wired differently internally to make them safe with the way we feed our 220 vs the way it is done in the EU? Things like Dryers have additional prongs for grounding, I believe there are even 5 prong receptacles these days. It's the simpler 3 prong ones for things like air conditioners that really have me wondering how they are made safe.

I know this is deviating from a more complex circuit like an amplifier with it's own power transformer but makes me curious none the less...

 

[WaynerN]

Me too! What spins in my head is how are these US devices wired differently internally to make them safe with the way we feed our 220 vs the way it is done in the EU? Things like Dryers have additional prongs for grounding, I believe there are even 5 prong receptacles these days. It's the simpler 3 prong ones for things like air conditioners that really have me wondering how they are made safe.

I know this is deviating from a more complex circuit like an amplifier with it's own power transformer but makes me curious none the less...

Why? Because in the US, each house is supplied with (2) 120 volt lines and a neutral by the utility. To get 240 volts, the (2) 120 volt lines are put in series. If you recall your basic electronics (if you ever had that), when two voltage sources are in series, they are added together, thus 120v + 120v = 240. Stoves, AC units and furnaces are designed with this in mind. The total 240 volts are used to run heating elements, or big motors. The stove (and other appliances) also use 120 volts to power clocks, lights and stuff like that. They get that from one leg of the 240 (120) and the neutral.

Our stereos are not designed for 240 volt. They are 120 volt. So there is a 120v line and a neutral to power our amps and preamps....etc. The neutral shall never be switched, nor should it ever be fused.

In EU and other places, they have 2 incoming lines, 220v and a neutral. Much different then ours. Hard to adapt from one to the other.

Hooking up an appliance designed for 220v in the US by suppling both sides with 120 volts makes the machine run, but it is an electrical code violation. One line (that is hot) will not be fused or switched, and there is no neutral present, which goes to earth ground via the electrical panel. If the unfused leg of one of the 120 volt lines comes into contact with the metal chassis, it has a 120 volt potential to ground. If the floor was wet and you were barefoot and there was a fault with the equipment, you possibly would be electrocuted.

 

[Sandstrom]

Thanks Wayner, thanks for the detailed description. I appreciate the detail, I understand everything you've written, my question was really as to how appliances, such as a 220 volt AC units are made differently than 110 versions in order to render them safe to use.

I am unaware of any A/C units with fuses/breakers (let alone 2) or multiple switches. Completely get how this is not a good plan for audio gear from EU, but am really wondering how other appliances are designed to appropriately handle this method of current delivery and how they seem to be fine with only the panel mounted breaker for safety in an overload situation. Was just curious how a circuit such as this is designed so that it can handle two hot legs and how it manages to do it safely.

 

[ducati_EL34]

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Hooking up an appliance designed for 220v in the US by suppling both sides with 120 volts makes the machine run, but it is an electrical code violation.

In EU and other places, they have 2 incoming lines, 220v and a neutral. Much different then ours. Hard to adapt from one to the other.

How so? I ma not following. Bear in mind, I have had a few by this time. A 220 double pole breaker straddles both legs coming in from the meter.

And yet, someone earlier said they did it for nine years. Like you said 120 plus 120 equals 240v. Instead of the EU way of 240 and 0 it is 120 and 120.

One line (that is hot) will not be fused or switched, and there is no neutral present, which goes to earth ground via the electrical panel. If the unfused leg of one of the 120 volt lines comes into contact with the metal chassis, it has a 120 volt potential to ground. If the floor was wet and you were barefoot and there was a fault with the equipment, you possibly would be electrocuted.

I can fuses to both lines, inside the amp.

If the floor is wet, I am not going to be reaching for anything electrical. I think you look for the worst possible scenario and base your opinion on that. Smart people will not fall prey tot that sort of thing. Dumb people, well, Darwin award time.

 

[maxhifi]

The European Shuco plug is not polarized, and as such, either side of the line may be connected to hot when it's used in Europe, depending on which way up the plug is plugged into the socket. Because of this, European appliances typically have a two pole power switch, which switches both sides of the line. The appliance doesn't know which side is neutral, since flipping the plug over will switch them, so neither line nor neutral will be connected to the chassis. An argument could be made that hooking it up to an American 240V outlet would actually be safer than using it in Europe, since the maximum voltage from either side of the line to ground will be 120, and not 230.

All of that said, be aware that using an electrical appliance in your house which doesn't carry a UL listing, could possibly violate your homeowner's insurance should there be a fire or any other incident.

Additionally, be aware that in Europe the nominal system voltage is 230, and that "240" in many American homes will be 250V these days. This may or may not create issues with the amp, it's about 10% high.

I choose to power my European equipment with a step-up autotransformer, where I adjusted the taps to provide exactly 220V to the amplifier I'm using. I bought it at Fry's electronics, in the USA, it was about $60 or so. Most step-up transformers of this sort are not isolation transformers, they are simply auto-transformers.

 

[Sandstrom]

The European Shuco plug is not polarized, and as such, either side of the line may be connected to hot when it's used in Europe, depending on which way up the plug is plugged into the socket. Because of this, European appliances typically have a two pole power switch, which switches both sides of the line. The appliance doesn't know which side is neutral, since flipping the plug over will switch them, so neither line nor neutral will be connected to the chassis. An argument could be made that hooking it up to an American 240V outlet would actually be safer than using it in Europe, since the maximum voltage from either side of the line to ground will be 120, and not 230.

All of that said, be aware that using an electrical appliance in your house which doesn't carry a UL listing, could possibly violate your homeowner's insurance should there be a fire or any other incident.

Additionally, be aware that in Europe the nominal system voltage is 230, and that "240" in many American homes will be 250V these days. This may or may not create issues with the amp, it's about 10% high.

You make a good point about polarity, I had considered that the pins could be inserted either way with the Shuco. I believe I can adapt a heavy duty US style IEC cord in this case as the step up I am getting should accommodate a US plug. I will just have to determine which is the hot and which is the neutral on the amp side, don't want to assume that it will automatically be the correct orientation. I also prefer the our grounding scheme better than how it's done with the Shuco.

 

[WaynerN]

Thanks Wayner, thanks for the detailed description. I appreciate the detail, I understand everything you've written, my question was really as to how appliances, such as a 220 volt AC units are made differently than 110 versions in order to render them safe to use.

I am unaware of any A/C units with fuses/breakers (let alone 2) or multiple switches. Completely get how this is not a good plan for audio gear from EU, but am really wondering how other appliances are designed to appropriately handle this method of current delivery and how they seem to be fine with only the panel mounted breaker for safety in an overload situation. Was just curious how a circuit such as this is designed so that it can handle two hot legs and how it manages to do it safely.

Great question. Our 240 volt appliances draw big time current, like 30-40-50 amps. Fusing them really would not work out so the panel mounted circuit breaker is the guardian for these types of appliances. They are not portable, and they are usually the only thing on the circuit and the breaker, whereas the hifi pieces share a branch circuit and are better off being individually fused.

I worked for a number of years as an industrial electrical designer, but my working voltages were 208 and 480 volt 3 phase stuff. That is nasty stuff, and a short could end up in a horrific arc flash explosion where it would be easy to lose life or limb or both. The NEC and NFPA-79e books were my friend during those years.

 

[ducati_EL34]

Great question. Our 240 volt appliances draw big time current, like 30-40-50 amps. Fusing them really would not work out so the panel mounted circuit breaker is the guardian for these types of appliances. They are not portable, and they are usually the only thing on the circuit and the breaker, whereas the hifi pieces share a branch circuit and are better off being individually fused.

I am curious as to why you think fusing 240v household appliances would not work? The condenser unit on an HVAC system has a double fused disconnect, as well as a circuit breaker in the panel.

I have worked in HVAC and wiring up such a circuit was very common. No inspection and no permit needed.

 

[Hyperion]

Just to clear up some peculiar ideas that seem to be circulating in this thread about UK/EU gear.

Inside 'modern' (guessing 1960's onward) electrical (household) equipment for use in the UK (and Europe) Live & Neutral are treated with exactly the same level of respect with regard to insulation. Neutral is NEVER connected to chassis in such equipment - unless you are talking about really ancient Valve (tube) gear.

The '240V - 0' confusion arises because we use one phase to create this, whereas, I think I am correct to say the US uses two phases to create a 220V supply - thus both live legs in this situation are 'hot' with reference to neutral.

 

[WaynerN]

I am curious as to why you think fusing 240v household appliances would not work? The condenser unit on an HVAC system has a double fused disconnect, as well as a circuit breaker in the panel.

I have worked in HVAC and wiring up such a circuit was very common. No inspection and no permit needed.

It's not necessary. They are the only appliance on the circuit and the circuit breaker can handle it. Stove...only device on the circuit. Furnace....only device on the circuit, dryer...only device on the circuit. Besides, they don't come with fuses.

In this state, we require a permit, but more importantly, it should be inspected by the state electrical inspector to protect the next guy that buys the home from the uneducated electrical work, done by the previous home owner.

 

[BigElCat]

It's my understanding that the two 120v legs are in phase with one another.

There is no dual phase, or two phase....only single or three phase (industrial) settings.

That's in the Conus. Continental USA.

 

[WaynerN]

It's my understanding that the two 120v legs are in phase with one another.

There is no dual phase, or two phase....only single or three phase (industrial) settings.

That's in the Conus. Continental USA.

Of course. Three phase stuff has 3 separate circuits (that should never cross-or you get an arc flash explosion) and each of those phases are 120° out of phase with each other. This is industrial stuff, used to run huge motors, furnaces and things like that.

Both legs of our 240 volt (which is 120 x (2) are the same phase, so when we combine them to make 240 volt, all is in phase.

The usable voltages for residential and commercial are: 120, 208, 240, 277 and 480 volt. 208 and 480 are 3-phase. 120, 240 and 277 are single phase. 240 is constructed from (2) 120 volt lines.

Single phase:

___________ 120, 277
___________ Neutral

240 volt:
___________120
___________120
___________Neutral

Three phase:

___________208, 480 @0°
___________208, 480 @120°
___________208, 480 @240°
___________Neutral

Some more fun stuff:

120 volt comes from a 208 volt, 3 phase "Y" system, from a center, neutral tap and one of the legs from the 3 phase 208 volt system.

277 volt comes from a 480 volt, 3 phase "Y" system, from a center, neutral tap and one of the legs from the 3 phase 480 volt system.

There is a 120/240 volt 3-phase 4 wire system, but for these discussions, it will only confuse.

 

[BigElCat]

That was in answer to Hyperion...just pointing out it's single phase even though we have two legs.