How to mark "110VAC" appilances for 12VDC

There are quite a few "standard" 12V connectors. That one rules for things meant to be used in a car.

Aside from having a few extra pins at (or at least for) other voltages, the 4-pin Molex for a PATA (and many SCSI) 3.5" computer hard disk or the newer SATA power connector are both common, inexpensive 12V DC plugs that work well, and can be recycled from junk computers. As an added benefit, if you need to derive 12V from AC, a computer power supply plugs right in. Sure, the first is a 12V/5V plug, and the second is

12/5/3.3, but they are _quite_ standard. And common.

--
Cats, coffee, chocolate...vices to live by 
Please don't feed the trolls. Killfile and ignore them so they will go away.

The EmPower connector is pretty good. It has an 8 amp limit (an Empower socket on an airplane supplies only 5 amps). It's nominally 15V which is close enough to the 12-14VDC that you get from a 12VDC socket.

Looks like a very good connector.

Googling has not been able to find a price, have you (sms) used this connector before and what did it cost.

Thanks

hamilton

Good grief. Tort illegal

Hot coffee isn't illegal, either.

You've said *NOTHING* that indicates it's illegal to use an AC plug on DC, anywhere. It's a horrible idea and certainly wouldn't get UL approval but that doesn't make it illegal. Not everything that's a bad idea is illegal.

On Tuesday, August 27, 2013 12:47:42 AM UTC-7, Martin Brown wrote: [About using 110VAC sockets for 12VDC power]

The US standard is the 'National Electrical Code' published by a fire safety organization, and it prohibits using wall-socket connections that are miswired in this way. It has nothing to say about wiring that is NOT part of a building, but there's good commonsense reasons to generalize from that recommendation.

Individual localities' fire-safety ordinances may differ from the standard.

Fuses, wiring, insulation, and sockets for 110VAC aren't generally safe for 12 VDC.

Please show me where "I" ever said it was illegal. I think you have my posts confused with someone else's. I agree that it might not be illegal to use an AC plug as the OP indicated.

But since you raise the point - (And I do admit this is a little bit of a s tretch, but here goes anyway..)

In an employer/employee situation, this would clearly violate OSHA's Genera l Duty Clause -- See 29 USC 654 5(a)1. Note USC. If you doubt USC as "law ", Wikipedia (Gak!) has a decent explanation under the Legal Status section of this page:

As to penalties (I mean, what's a good law without any penalties?), refer a gain to the OSHA Sec 17-e. Prison. Done.

So yeah - that's a stretch I'll admit, but there's one law right there that arguably says it's illegal to use the connector as the OP suggests, at lea st in connection with employment.

"whit3rd"

** Not true at all.

snipped-for-privacy@alphaquest.com wrote on 27/08/2013 :

Hasn't this gone on long enough? :-?

It is bad practice whatever excus you might make for doing it.

Just use a different plug and get on with your life. :-Z

And let the rest of us get on with ours. :/

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John G

"John G"

** The OP has only a small number of these in use and likely they are away from AC power at the time.

Change the plugs over and the lamp has no other use, leave the plugs alone and they can be used for 120VAC again any time you care to swap the bulbs.

... Phil

Anyone notice the absence of the OPer ?

Electrocuted himself?

What dangers do you forsee? It's not like arcing is much of an issue at 12V.

For the same bulb power, you dissipate a lot more heat in the crappy brass/brass connectors. The resistance can be enough that you can start a fire before you blow the fuse. (That's the reason for the rule against daisy-chaining extension cords even at 120V, iiuc.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

Assuming the same current limit, of course. Geeze. ;-) Switches are almost always rated by current, not kVA or watts.

Many mains-rated switches also have a low voltage DC rating (30V or less). I've never seen one with a lower current rating, have you? Usually it's the same at 28VDC as at 125VAC, and less at 250VAC

Of course at _high voltage_ DC (eg. 125VDC), the current rating is usually MUCH lower, or not recommended at all.

BTW, I'd worry a LOT more about the thermoplastic extruded line cord than the switch. Especially if it's coiled up. Fortunately, the typical Edison-base 12V lamp is only 50W, so it draws less than 5A.

It's hard (but maybe not impossible) to make a UL-listed line cord flimsy enough to get dangerously hot at

What rule? Or is it a US-specific thing? UK extension cords use the same male plugs as the appliances so I don't see why you can't daisy-chain them.

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John Devereux

It's in most local fire codes over here, afaict. It's certainly in ours--when the fire marshal comes round for his occasional visits to stores and offices, it's one of the things he'll ping you for. Whether he can actually do anything about it, I don't know. Probably not, but the insurance company might find out if there was a fire.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net

What statement did you answer (that you conveniently snipped)?

Wring. Learn to read.

Nonsense.

Now, show me where this has *ANY* relevance to the discussion.

Idiot.

Just admit that you're talking through your ass.

But I don't understand the mechanism. I suppose it makes it easier to overload them, if you have a 1:4 way say with 4 more 1:4 ways spidering out from that.

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John Devereux

This may be just a guess, but I thought it was because the high resistance of a very long light gauge cord could cause excessive voltage drop.

If the load is more-or-less resistive there could be overheating if the extensions were coiled up, but more importantly if the load is something like a compressor (eg. refrigeration or a/c system) the high start-up surge could cause the motor to stall when the thermostat or pressure switch calls for it to run and draw a lot of current, maybe causing a problem in the motor or elsewhere.

UL does allow cords to be rated for less than the typical 15A capacity of an outlet, so two 7A cords plugged into each other might represent a problem.

There's nothing physically preventing you from plugging a 1500W heater (13A) into a 7A extension cord though. Or a 1500W heater and a 1200W heater and plug it into a 20A outlet .

BTW, they also do not like extension cords used "permanently". Most of us have an extension cord or power bar somewhere like that, but if it's hidden behind molding or whatever they can bitch about it. I've seen extreme cases where an entire industrial unit was being run from a few outlets at the power entry (the guy didn't want to pay an electrician, and the units come without interior wiring). For some reason ;-) the Chicago FD is particularly picky if you end up having to deal with them.