Questionable Test Equipment

[journeymenelctric@msn.com]

I have a piece of test equipment from another country, which requires 50 hertz +-5% and 220 volts +- 10%. Available power on site is 120/208 volt 3 phase, 60 hertz. The customer is wanting the equipment installed says they have these elsewhere in the U.S. and 60 hertz is okay to use on this equipment, does anyone know of any problems with this?
Also, the 208 volts is within tolerance but their 220 volt requirement is a hot leg and a neutral, here it would be two hots, the equipment is single phase. Any thoughts, any experiences, or code input would be greatly appreciated.

 

[GoldDigger]

Among the things that might cause problems operating from two hots would be any surge suppression or RF filtering elements built into the device.

There have also been instances involving commercial (restaurant) heating equipment where applying standard US 120/240 caused balanced capacitive leakage to ground which did not trip a GFCI but using two hots from a three phase supply would cause a trip.
That is the opposite scenario, but is still an indication of the sort of thing that might go wrong.

If the supplied power is simply the input to a switching power supply with isolation, it is far less likely that there would be a problem.

If your inspector is looking for a UL sticker, then your customer has a problem.

 

[journeymenelctric@msn.com]

There is no GFCI, won't be an issue. They say they have used this equipment in Wichita, with no issues. Just trying to be careful and cover all aspects. Thank you for your input, much appreciated.

 

[winnie]

Having dealt with the analogous issue of switching power supplies fed at 400 Hz, basically it will probably work but you are running the equipment out of spec so you have no guarantee.

In addition to the issues mentioned above, you might see things like only the intended hot leg switched.

If this equipment is intended to be plugged in, many European plugs are not polarized so the equipment can't depend on a grounded supply conductor.

Jon

 

[synchro]

... Also, the 208 volts is within tolerance but their 220 volt requirement is a hot leg and a neutral, here it would be two hots, the equipment is single phase. Any thoughts, any experiences, or code input would be greatly appreciated.

Among the things that might cause problems operating from two hots would be any surge suppression or RF filtering elements built into the device.

The 60 Hz frequency is less likely to cause damage or issues than the requirement for one leg being a neutral, which might lead to problems with internal surge suppression or EMI filters as GoldDigger has brought up. It's possible that such problems would occur but the equipment would still be basically functional and so these issues would not be immediately apparent.

A transformer could be used to create an output with a grounded leg, and if this is relatively low power test equipment the transformer should have low cost and size.

 

[journeymenelctric@msn.com]

Thank you, I will present these concerns to the customer. Thank you very much for your inputs.