6-15R/6-30R compatibility

I looked at the descriptions of the plugs.

As I read it, the 6- is for 250 volts grounded service (no neutral.)

The grounds are different sizes (it looks like the lower amp plug has a larger ground).

IF you don't need the ground, it looks like the 15 WILL fit into the 30.

Slight OT: I picked up a 120 volt room A/C a few months ago. The actually A/C unit is UNGROUNDED! The cord set has a built in GFCI as part of the plug. The plug does have a ground pin but except (perhaps) for the "Test" function, it is not connected.

Not that much of a risk. He might want to replace the 30 amp breaker with a 20 amp (it's hard to find 15 amp two pole breakers).

Hi, dan

Manufacturer always make profits but sometimes leaks of technical knowledges. Before you decide to use whether 6-30R or 6-15R, suppose you should know what house power (HP) the air cond is?. then come to socket and breaker. If < 2.0HP where running currents is about 7 - 8A, better still you use 6-30R then breaker suppose 30A or 32A. It should be fine. Newer forget that the cable used for socket shall be considered also. I am really not sure in your county. But, commenly used with cable size

tks

magic

| I have a quick question that I hope I can get a simple answer to ... | I've been put in charge of purchasing a new air conditioner for my | workplace, and before I buy one I want to make sure the new plug is | compatible with our existing outlet. The air conditioner we have now | has a type D plug (6-30R) and the one I am planning on buying is type B | (6-15R). The salesman at the appliance store assured me that a male | 6-15R will work in a female 6-30R socket, and I am just hoping to | validate that information before making this purchase. I know that the | shape and configuration of the prongs is the same, but I am unclear if | the size difference will make a difference. Can somebody help me out | with this? I'm clearly not an electrical engineer but I though this | would be the best place to get an educated answer. thanks

The male 6-15P (the "P" means plug ... e.g. the male end) will NOT mate with a female 6-30R (the "R" means receptacle). The size is substantially different. The 6-30R is the same size as a home dryer outlet, but with two blade slots turned horizontal and one round hole. The 6-15R and 6-30R do look alike other than for the size. The 6-15R (and its 6-20R cousin) is the same size as a normal home outlet (5-15R and 5-20R).

Since this is a workplace, it is illegal for you to change the circuit (you clearly are not a licensed electrician, though certainly wise enough to be sure to ask the right question).

A licensed electrician experienced with commercial settings would be able to replace the receptacle with a 6-15R, and replace the breaker with one rated for 15 amps. It should be under 30 minutes of work if everything is normal.

Be sure you have the air conditioner present when the electrician does the work so he can oriented the receptacle most appropriate for the way the plug is attached to its cord.

Absolutely never take any electrical advice from that store salesman.

If it were me, I'd look at larger air conditioners that would have a