230V Audio Equipment use in the USA

Discussion in 'General Electronics Chat' started by JCPrice4u, Dec 31, 2014.

  1. JCPrice4u

    Thread Starter New Member

    Dec 31, 2014
    I would like to request some assistance as the more I research the more questions arise.

    While living in the Middle East I purchased some fairly expensive audio equipment for home theater. Of course all of these are 230v 50/60Hz. When I returned to the states I shipped them home assuming I would be able to hook them up with not issues. Now I am not so certain.

    I'll begin by listing what I want to connect.
    Surfire Theater Grand Processor 4 (40 Watt)
    Sunfire Signature Grand Amp 7/400 (1800 Watt)
    Denon DVD A1XV (80 Watt)
    Definitive BP3000TL (1000 Watt X 2)
    Definitive BP2000 (300 Watt X 2)
    Definitive C/L/R 3000 (150 Watt)

    These are peak requirements. I doubt very seriously I will use more than 3000 watts and most likely far less as I live in an apartment complex and won't be able to use the system any where near its full potential.

    I understand in a 220/230/240 volt country this is achieved with 1 hot, 1 neutral, and dedicated ground. I now know here in the USA in a 240V AC circuit we drop the neutral and use 2 hots.

    I don't believe I can supply 240 volts developed in this manner to my equipment however I have not gotten a definitive answer on this subject. Of course any business selling step up transformers will tell you no you need a transformer. Do I need a step up transformer to connect this equipment or can I use an American Nema 10-30 on a 30A breaker tying the ground to neutral? I know this is not to code however I've read that if you are not using a 110V leg in this circuit it is premissible. I can do a leakage current test once its hooked up to ensure there is no voltage present on equipment cases.

    I have researched the step up transformers being sold to consumers and I am not impressed. There seems to be a wide gap between industral commercial grade step up transformers and step up transformers being sold for home use. If this is the path I need to go I would welcome any educated suggestions.

    I would choose 120V to 220V step up transformers. I would utilize 3 separate 20A circuits placing 600 watts on a 1kVA on 1 circuit, 2000 watts on a 3kVA on 1 circuit and 2070 watts on a 3kVA on the 3rd curcuit.

    Unless some one with user experience can change my mind my thinking is most or what is available is of very poor quality and not much better than garbage.

    I would like to ask is it possible to purchase 1kVA and 3kVA commercial transformers, at a reasonable price, that would allow me to supply 120V from a NEMA 5-20 circuit and have the option to output 230V. If available, even if they require hardwiring, I can easily attach the 120v power cords for input and BS1363 power strips to the output terminals. I'll mention I intend to use BS1363 13A power strips and plugs once I find the solution that will allow to get this system connected and working.

    Any help you can provide would be greatly appreciated.

    Thank You.
  2. solaris9123

    New Member

    Dec 23, 2014
    it's possible to use the L1 and L2 legs of the circuit breaker to make 240V without a neutral.
    many 2 wire appliances in the US do this, but as far as the audio equipment, i think it would be safer to use a step-up transformer.

    i'm not an engineer; that's just my opinion
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    You are right to be cautious.

    Your neutral connection is locally grounded so you will not be able to use your equipment without an isolation step up (1:2) power transformer.
    These are readily available and your choice should be for one whose continuous RMS rating equals the continuous RMS power of all your equipment setup.
    The peaks will take care of themselves.
    There should be a rating plate on each separate piece of equipment. Just add up the ratings.

    I can only imagine you live in the next county from your home cinema if you need 3 kilowatts.

    Last edited: Dec 31, 2014
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
    I am a US amateur radio ham. My high-power RF amplifier has a power supply that requires either 120V @ 20A, or 240V @ 10A. It is much preferred to run this amplifier on 240V, so when I built an wired my Ham Shack/Electronics Lab, I ran a dedicated 240V outlet for the amplifier (separate ganged breaker in the panel). That outlet uses a twist-lock socket that brings out all four wires, L1, L2, N, and Gnd., like you find on a welder or other industrial equipment.

    While I was at it, I wired all of the standard 120V 15A duplex outlets in the entire lab for 240V. Huh, what did he just say?
    I used #12AWG wire; red, blk, wht, and grn to each outlet box. In the Panel, this wire goes to a 240V 20A ganged breaker. At each outlet, by breaking out the built-in tab, the blk wire goes to the top plug narrow blade, the red wire goes to the bottom plug narrow blade, the wht goes to the two neutral wider blades, and grn to the ground, as usual. This way, any standard 120V device can be powered any where. On the off chance I need 240V anywhere in the shop, any given existing outlet can be converted to a 240V socket in a few minutes time...

    Oh, and for all of those who were going to pop on and tell me that this is illegal, etc, the county inspector is fine with it...

    Any licensed electrician can put a 240V 20A to 30A outlet anywhere you want it (think electric stove or close dryer). This is easy if you own the house; not so easy if you are renting.

    ps: I found this manual on-line. This suggests that this amp will run on either 120V or 240V, but no change-over instructions are provided. Unlike my RF amp, which has a split primary power transformer that can be rewired in the field for either 120V or 240V input where the manufacturer puts the rewiring instructions right in the manual.

    I'll bet that your amp also has a split-primary transformer, and can be changed over. Contact the maker and see if they will help you....

    Your cumulative power requirements are way too high to do this with a step-up transformer.

    pps: I just looked at some of your other stuff, and noticed that it likely uses SMPS power supplies, which likely need no change-over; they typically will take anything from 100V on up. If that is the case, changing the line cord plug is all you need to do...
    Last edited: Dec 31, 2014
  5. studiot

    AAC Fanatic!

    Nov 9, 2007
    Interesting, Mike.

    There is no doubt that you can obtain 240 from the 'interphase' voltage to feed properly isolated transformers within equipment.

    But equipment sourced outside the USA may well have grounded one part of the internal supply so the $64,000 question is

    How did you treat ground in this situation, since the centre of the 120-0-120 US supply has to be grounded?
  6. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Most of the this equipment was sourced in the USA, and then exported.

    It is highly likely that all of the listed audio equipment is wired with a three wire cord, where neither side of the 240V input line is connected to chassis ground inside the audio equipment; only the third wire (ground) is connected to chassis.

    30seconds with an Ohmmeter would answer that question...
  7. MaxHeadRoom


    Jul 18, 2013

    I have used European equipment on N.A. 240v 1 phase with no problem, European equipment has, or should have, the same stipulation as N.A. equipment where it is use against the code to connect neutral and ground conductor at any other place but the service entry.
    Having practiced electrical and electronic profession in UK I am familiar with the regulations both sides.
    The exception in N.A. is if a 120v isolation control transformer is used it is permitted to set up a 'local' ground by connecting one side of the secondary to earth immediately at the transformer output.
  8. crutschow


    Mar 14, 2008
    I would think you could use an autotransformer, which is cheaper and smaller than an isolation transformer, if you go the transformer route.
  9. MaxHeadRoom


    Jul 18, 2013
    N.A. 240v does not 'drop' the grounded neutral, it is just referenced at a different point.
    About the most economical answer is to measure both input conductors of the equipment to see if either are referenced to ground, I would be very surprised if it were as that would mean disastrous results if any one in the original country were to inadvertently alternately connect the L & N!!
    If both conductors measure essentially open circuit to a grounded case then it should be perfectly fine to hook up to N.A. 240v power.