5-15R Frequency requirement.

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C

Crown Electrical

BBKing
Location
Michigan
Occupation
Master Electrician/designer
Ran into a situation where several Auto Transformers have been used to adjust voltages down to 120 volts from a 230 volt 50 Hz system.

Then 5-15R plugs were installed for customer to access power and plug 120 volt 60 Hz equipment (from the United States).

When I see this plug I expect 120 volt and 60 Hz. I am concerned that the frequency is actually 50 Hz .

I do not see in the NEC code where there is a requirement for 60 Hz and am unable to find a reference on line with the NEMA requirement for this plug.

I am concerned that this may be a safety issue.

Linear and non-linear loads are used.

Thank you in advance for your comments.



NEMA 5-15R.jpg
 

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The receptacle doesn't care. It's not using power, it's merely transferring it from the conductors to the load(s).
 
I'm not sure how much can be done about that.

The National Electrical Code isn't regulatory or enforceable by itself, only when local jurisdictions have enacted it into law. And I'm pretty sure that hasn't happened in places with 50-Hz service.

I also don't recall seeing anything from NEMA specifying frequency, only voltage & current. Or anything in the NEC mandating adherence to NEMA conventions. They just sort-of assume 60 Hz because NEMA is a mostly-American organization.

I'm also not sure just how much of a hazard this is. Yes, some induction motors will run slower and hotter, but I doubt many of those motors will be carried to other countries in American tourists' suitcases. And maybe they dial the voltage down to 105-110 volts to prevent that.

It would be up to the regulatory agencies in the individual countries where this happens.

480sparky said:
The receptacle doesn't care. It's not using power, it's merely transferring it from the conductors to the load(s).
Click to expand...
True, but you'd sure raise a fuss if you plugged a portable device into a 5-15R and it transferred three phases of 480 volts.
 
Where are you getting this 50 Hz from? I understand that there are some old hydro systems still left in Michigan.

How many of these receptacles are there? What do you use 50 Hz for? I ask to see whether it would be worth it to either change the receptacle circuits to 60 Hz or change the receptacles to something non-standard. As far as I know there is no standard for a 50 Hz receptacle. The situation is also that most equipment will have no problem with 50 Hz.

-Hal
 
You will also encounter this sort of situation on an airplane, where you will often find 5-15 receptacles with 115V 400Hz on them.

-Jon
 
Transformers do not alter frequency. 50 hz in/50 hz out.

I am working in a foreign country at this time.

I am looking at this from the point of view of consumer and their expectation (60 Hz/120 volts/max of 15 amps)

Attached is a spec sheet for for a 5-15R.
 

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I say the user should know the frequency his/her equipment is rated for, and should find out the frequency in use there.
 
Equipment with internal 60Hz transformers, may not be happy with a 50Hz supply even if the voltage is correct. Newer equipment with an internal SMPS (power supply) probable don't care if it's 50Hz or 60Hz.
 
This is not an NEC issue. And I am thinking the assumption is this 5-15R is used in USA with 60 hz. In the country you are in, are you under the scope of the NEC or some other standard? If not the NEC, what does your standard state?
 
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