Mechanical Engineer Needs Help 1

[Essex57]

Apologies for asking such a basic question, but it is 35 years since my last electrical engineering lecture at London University.

The question is hypothetical (to solve an argument with a colleague).

I live in the US and want to put a 220V socket in my house , which is wired to 110V. How is this done?. For example will I need a transformer, can I split a 220V wire into 2 x 110V by a simple method?

 

[itsmoked]

In the US houses are generally supplied with two 120V circuits 180 degrees out of phase. This means that taken together the two different HOTS provide 240V.

If you want a 240V outlet and your house really is supplied only with 120V then you would need a transformer. HOWEVER, if your house is only supplied with 120V then the wiring will be woefully old and limited and you should not be adding any 240V loads!!!!

Get an electrician and a permit and do it up right. It will make your house a great deal safer than it is now, and increase its value.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[sreid]

If you have 3 wire service comming to your house, you have 240 V service.

 

[rbulsara]

Essex57:

I am a bit concfused as to what you want. You said "want to put a 220V socket in my house , which is wired to 110V", then you talk about splitting 220V into 110V? What are you looking for?

Since your question is hypothetical, here are the facts:

For all practical purposes, all US residences have 240/120V or 208/120V service, which includes 2 hots, one neutral and a ground wire. Voltage between 2 hots is 240 or 208. Voltage between any hot and neutral is 120.

A 220V outlet will be wired to the two hots. A 110 or 120V outlet will be wired to a hot and the neutral. 220V outlet will require a 2-pole breaker.

If you are replacing a 110V outlet with 220V one, you can reuse existing wires but then the white wire will have to be re-identified correctly with black/red color so that it is not mistaken for neutral again. Also you will have change the breaker at the panel and do related rewiring.

Besides, this forum is not for home projects. So copy this before it gets red flagged.

For more sit down with an electrical engineer/electrician friend.

 

[IRstuff]

>>>I live in the US and want to put a 220V socket in my house , which is wired to 110V. How is this done?.

My house is supplied with 2 phases of the 3 phase supply to my neighborhood. Load balance is done by distributing different sets of 2 phases to different houses. If you look at your breaker box, you'll see that the house breakers are distributed on different phases, so that the ceiling lights might be on one phase and wall sockets on another, while the built-in oven might have a doubled-breaker running to both phases.

Unless the wiring already exists, you'll at least need to pull wire from the other phase to your socket, AND you'll need to change the breakers accordingly. For example, wiring an 220V electric dryer will require pulling both phases to the dryer, in addition to the neutral and installing the correct wall socket.


TTFN

 

[Comcokid]

Many houses will already have a 220V socket at the electric clothes dryer. Electric hot water heaters and central heat/air units are 220V, but are usually hard-wired.

 

[felixc]

An electric stove/oven will also be connected to a 220-volts outlet.

 

[VEBill]

We should probably ask what appliances are planned for this outlet? Reading between the lines a bit ('Essex...' & London U.), I'm guessing you've got an old UK appliance that you'd like to try.

Those mentioning stove and dryer outlets were intending to make the point that almost every house in North America already has several 230VAC outlets (just to make the point). But this certainly doesn't mean that you should start your experiments with such a high power outlet (over-current protected at, for example, 40 amps). If something goes horribly wrong then you might have a larger-than-necessary smoldering crater (slight exaggeration) in the middle of your kitchen or laundry.

There are standard sockets (North American) for 230VAC outlets that aren't quite so high power as dryers and stoves. Personally, I've got a 230VAC 20-amp socket in my basement for use with my plug-in air compressor. It's the proper socket for the purpose (NOT a miswired normal outlet as is sometimes done).

There are also standard 230VAC 15-amp sockets too (different pin arrangement than the usual 115VAC version).

Be very aware that North American 230VAC is HOT and HOT. I believe that most UK appliances have plugs that can be inserted either way around so that seems to indicate that either side can be HOT without any problem.

This might not apply to some older appliances. The UK was famous for the funny nonsense of the brand new appliances not being supplied with plugs because they had too many standards.

Note also the 60Hz versus 50Hz. Usually not a problem, but clocks might run 20% fast.

Useful ref:

http://en.wikipedia.org/wiki/Domestic_AC_power_plugs_and_sockets

 

[ScottyUK]

I believe that most UK appliances have plugs that can be inserted either way around...

Only if you use a hammer! Actually there are European two pin plugs which can fit either way around but in the UK you need an adaptor to use them with a standard three-pin 13A outlet.

Most equipment doesn't actually care which AC pole is live or 'hot', but the live conductor is fused in the plug. We don't do cute tricks like using the earth conductor as a neutral (or vice versa) like I read about on Eng-Tips from time to time, so the insulation is usually uniform throughout the appliance.

----------------------------------

Sometimes I only open my mouth to swap feet...

 

[VEBill]

Thanks for that correction ScottyUK.

 

[richs]

Hiya-

And there was NO discussion of 50Hz vs. 60Hz. I would
be very reluctant to plug in a refridgerator designed
for 50Hz into a 60Hz system. Might be very interesting
with syncronous motors in clocks, etc, etc.

Transformers for power supplies (like radios and stuff)
will be o.k. with the 50->60 issue. (There is more iron
required for 50Hz and so will do fine on 60Hz) but
all in all it could be "interesting".

We always hedge our bets.

Irsmoked has the best suggestion. You don't have to hire
an electrician, but if you have one as a friend, and
explain in detail what you want to do, it would be a
VERY good idea.

Cheers,

Rich S.

 

[itsmoked]

Hi Rich!
I actually had 'friend' written down then thought... If he was taking his house from 120V to 240V he has to involve an inspector, and the utility, which would likely exceed the 'friend level' or at least reach a level where the friend might be taking on more than required to maintain a friendship..

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[VEBill]

"...was NO discussion of 50Hz vs. 60Hz."

I mentioned that issue briefly (just above the 'wiki' link).


If I wanted to use a UK appliance (assuming it can handle the 60 Hz and other considerations), then I'd wire up a proper and legal 230VAC outlet (15 amps should be enough) as per North American standards, and then make up my own adapter cable with a UK socket at the other end.

Or cut off the UK plug and rewire the appliance with the correct mating NA plug.

 

[rmw]

"In the US houses are generally supplied with two 120V circuits 180 degrees out of phase."

I thought the two phases were 120 Degrees out of phase?????

rmw

 

[jraef]

They are if derived from a 208Y120V 3 phase system as you would find in a commercial or light industrial service, but most residential services have their own dedicated transformer giving 240/120 1 phase and the 2 hot lines are 180deg out.

JRaef.com
Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[richs]

VE1BLL & itsmoked

Apologies to both of you! My bad. Yep, I think that
dollar signs are in order and a squint by an inspector
would not hurt in the least.

*MANY* tricky situations that could cause bodily harm and/or
fire.

Cheers,

Rich S.