what is this plug for ?

[zukmancdr]

what is this plug for? I have two on my bus, one in the front and one in the back.

[hargreaves]

usually used for powering lights while the coach  is in the station. I plugged mine in and got a large humm for about 2 minutes and then tripped the breaker in my garage.    Cheers Gewrry

[zukmancdr]

thanks for the info. I was thanking it had something to do with the a/c.

[lvmci]

zukmancdr, that in normal home or commercial use is a higher amperage Edison Plug. The normal plug we see at home is two vertical blades, one on left looking at it, is common, smaller one is power, round one on bottom is earth ground. the next higher amperage Edison is one vertical and one horizontal and a round earth ground and the next higher Edison plug after that in amperage is the one pictured, however any one can use a plug for any purpose, to discourage anyone from pluging in a standard plug that would do damage to something, lvmci...

[Bussman84]

Mine also had one in front one in rear, front one for parcel lights and baggage lights. Rear one went to block heater.

      HTH......Billy

[zukmancdr]

Mine also had one in front one in rear, front one for parcel lights and baggage lights. Rear one went to block heater.

      HTH......Billy

thanks

[Sean]

... that in normal home or commercial use is a higher amperage Edison Plug.

I believe you might be confusing voltage and amperage.  Unless I am missing something, the connector shown is a 15-amp connector, which is exactly the ampacity of a standard household outlet, except this one is for 250-volt nominal systems.  Typically this is derived from the leg-to-leg voltage of either a split-phase system (220-240 VAC) or a three-phase system (208 VAC).  (The 30-amp, 250-volt connector is similar, but larger.  I can't tell for sure from the photo, but I am pretty sure the station lighting is a 15-amp connection, as is the block heater).

Also, "Edison plug," while not incorrect, is a term not really used in the electrical industry, outside of the theater and movie gaffer/grip trades.  The more common terminology is "NEMA," which stands for National Electrical Manufacturer's Association.  The pictured connector is technically a NEMA 6-15P.

... however any one can use a plug for any purpose, to discourage anyone from pluging in a standard plug that would do damage to something ...

This is not correct.  Plug and receptacle voltages and ampacities are strictly governed by code.  You are not permitted to use a 250-volt plug for 120-volt service, because of the danger that someone might accidentally connect it to a 250-volt receptacle, in which it would fit.  The whole NEMA panoply of plugs and receptacles is designed to prevent exactly this.  (There is a limited exemption for systems of 30 volts, nominal, or less).  The idea is that simply looking at the plug or receptacle will tell you what voltage and ampacity it uses, and only connectors of properly matched voltage and ampacity will mate.

There are, however, accepted methods to achieve what you describe.  Most typically, a locking-type plug and receptacle are used to discourage casual use of receptacles or unintended connections to plugs.  Every straight plug and receptacle has a corresponding locking type, so in the case of 15-amp, 250-volt service the correct connector would be a NEMA L6-15, where the "L" stands for Locking.

FWIW.

-Sean
http://OurOdyssey.BlogSpot.com

[lvmci]

I stand corrected, the proper and technically correct installation is as stated. Yes I come from the TV & film industries, & yes utilities/grips, stage electricians and set construction use unusual and quick fixes to solve temporary problems, my meaning was to inform of multiple levels of power connectors, that anyone may install after a trip to the hardware store, as I have experienced in my own rvs.lvmci...