Larry Green wrote, On 16/08/08 00:05:
> Flash Gordon wrote:
>> Larry Green wrote, On 15/08/08 21:26:
>>> Flash Gordon wrote:
>>>> Hello all, a bit off-topic, but I have a question about power in the
>>>> USA...
>>>>
>>>> On of my brothers is moving to Silicon Valley (he has a 3 year work
>>>> visa and his new company will sponsor him for a permanent work visa)
>>>> and has a lot of expensive 220-240V Hi-Fi & AV equipment. One of his
>>>> mates has said that houses often have 240V in the garage and
>>>> kitchen. So what we want to know is whether the power is coming in
>>>> to the house at 240V and then being stepped down so he would be OK
>>>> running a 240V circuit to the lounge or whether it is stepped up for
>>>> the garage making this a bad idea.
>>>>
>>>> To bring this nearer to on-topic, do they have silicon chips and
>>>> microfiche for supper in Silicon Valley?
>>>
>>> I am not an electrician but houses over here typically have both 110V
>>> and 220/240V feeds but the 220/240V feed is usually a two-phase
>>> supply (i.e. two lines of 110V) not a single phase supply like the UK.
>>
>> That would be likely to cause problems.
>>
>>> The 220/240V source is usually ONLY fed to washer/dryer units or
>>> electric stoves/ovens and not to the rest of the house.
>>
>> Hence the suggestion by his mate of adding a new circuit :-)
>>
>>> In fact supplying 220/240V to any other location may well be breaking
>>> the local wiring codes in many cases.
>>
>> That would be a problem if he gets caught ;-)
>>
>>> IMHO his best bet would be to sell all his 220/240V electronic
>>> equipment over there where it has some resale value rather than
>>> paying a large amount of money to have it shipped over here only for
>>> it not to work.
>>
>> His new employer is paying for the shipping so he is not bothered
>> about how much that costs :-)
>>
>>> He could get the same gear for less money on this side of the pond
>>> anyway (unless it is high-end Brit stuff of course!)
>>
>> It is high-end stuff, at least some of it high-end Brit stuff (the 5
>> power amps, one per speaker, are high-end Brit stuff).
>>
>>> Something else to think about is the AV equipment, depending on just
>>> what that equipment is it may not even be compatible with the
>>> equipment in use over here.
>>
>> Only the power supply is a problem.
>>
>>> Europe (with the exception of France) runs on the PAL system for
>>> TV/video whereas North America is on the NTSC system and the two
>>> systems are not compatible.
>>
>> As to that, both of us know a lot about that, including *why* NTSC has
>> been known as "Never Twice the Same Colour[2]"[1]. It is not a problem
>> for most of this (and a of of other) kit.
>>
>>> HTH
>>
>> It does help suggest this could be a bad plan.
>>
>> [1] It's basically (with simplification) because when broadcast over
>> the air each colour can take a different path and thus take a
>> different amount of time to reach the receiver leading to colour
>> instabilities unlike PAL which is approximately a B&W + deviation from
>> white where this can't happen.
>>
>> [2] The "u" is specifically included to further wind up the Americans ;-)
>
> Hmmm .... sounds like he has some nice gear there hence the reason to
> bring it with him. ;-)
Indeed.
> If he can find a 'conversion transformer' to go from 110V to 220/240V he
> might be better off going that way.
There are several potential problems with that including the amount of
power drawn by some of this kit (power amps need power!) and how good
the step-up transformers are at giving a nice smooth supply.
> One other thing to consider is the 50/60 Hz difference too. In most of
> the Americas the electricity supply is at 60Hz while most of the rest of
> the world runs at 50 Hz. I don't think it will be a problem with his
> audio/AV equipment as it will be stepped down to a low voltage DC supply
> in the front end of the equipment anyway.
He has already checked that some of the expensive kit can run off 60Hz :-)
> Depending on the total current draw of the equipment he wants to run he
A lot. The power consumption of *each* power amplifier is 500W so you
would need one of the 800W converters (they cannot run continuously at
maximum power) at $49.99 per power amp, or one of the 3000W ones (the
continuous output of the 3000W one is not enough) at $149.99 for all 5.
Then there is the rest of the kit. It might be even worse if there is a
surge on kit being switched on (which is entirely possible on power amps
and any high-power kit) so this would need to be checked out.
> could plug a UK power bar into a transformer and run several items at
> once if need be as long as the step-up transformer is big enough to
> supply the power required. If not then more transformers (one for each
> piece of kit maybe) could be the answer.
It would be a number of the expensive plug in ones to power all of the
kit safely (or maybe one hard-wired one) each of which has
inefficiencies leading to extra power consumption and heat.
> I think that approach will be
> far cheaper than trying to run 220V/240V around a left-pondian house
> even if he could do it within the local codes. Remember too that in many
> places in the US a homeowner is NOT allowed to do ANY rewiring as it can
> only be done by licensed professionals.
The easiest thing is spending a lot of money on replacing all of the
expensive kit, although some of it is not as expensive as when he first
bought it.
--
Flash Gordon
