How to use two 30 amp receptacles and get 50 amps

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dbuckley

Senior Member
Thats not quite what it does; it turns a pair of 30A 125V outlets into a 30A 250V supply presented on a 50A 250V receptical.

So no black magic involved. And so much better than the version you're more likely to see, which is just a couple of plugs, a recptical, and some wire - ugh.

My very first post on this forum was enquiring about the legality of these bodge cable adapters, often seen being used by bands in bars...
 
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curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Tom, I don't see where they are stating you get 50 amps from this adapter. It is designed to be used with boats that have a 50 amp 120/240 volt connection. If you only have a 30 amp 120 volt connection available none of your 240 volt loads and 1/2 of your 120 volts will not function. This adapter lets you use 2 standard 120 volt 30 amp connections to obtain a 4 wire connection but you are still limited to 30 amps. It has built in protection incase the receptacles are miss wired or 1 of the connectors in not plugged in. I'm sure there are many home made versions of this adapter in use but they can be very dangerous so Hubble has designed a safe version.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I'd be interested in knowing how the device handles the you're-not-supposed-to-parallel-small-conductors issue.
 

stew

Senior Member
Thes are in use by folks in our yacht club all the time. a very convenient way to use the existing 50 amp cord. Read closley and you will see that it states 30 amps avail and not 50. It also states the "most" of the boats electrical will function ok. On a boat that is this large typically 48 ft and above 30 amps is a bit small. As long as they dont run the ac etc things work pretty much ok. The savvy boat owner knows which breakers to deactivate when using this system to prevent the dock pedastal breakers from tripping.
 

wireguru

Senior Member
I'd be interested in knowing how the device handles the you're-not-supposed-to-parallel-small-conductors issue.

this doesnt parallel them. Its two 2P3W plugs to a 3P4W receptacle, designed to be plugged into two receptacles on different phases. The box in the middle contains circuitry and a contactor / relay to keep it from operating in a dangerous mode (one plug disconnected, both inputs on same phase, etc)
 

480sparky

Senior Member
Location
Iowegia
Then I don't understand the "Y" concept of it then. If the dock power is 30a, and you have a 50a cord, then all you need is an adapter. RVs use them all the time, but not in a "Y" configuration.

What's to be gained by plugging into TWO 30a receptacles if you cannot get any more than 30 amps out of the thing? The same thing could be accomplished by using a M-F adapter into a single 30a recep.

I have seen cords for stage & theater that utilize two 120v receps to obtain 240v, though.
 

wireguru

Senior Member
I have seen cords for stage & theater that utilize two 120v receps to obtain 240v, though.

this thing is a safe version of that.

The 50a receptacle is 120/240 -2 hots, a neutral, and ground. One 30a goes to X and neutral, the other 30a goes to Y and neutral.
 

Cavie

Senior Member
Location
SW Florida
Go back and read it again. It is not even with two different phases. It states it MUST have two different phases. Not 50a availible. It will trip at 30.
 

Smart $

Esteemed Member
Location
Ohio
I'd be interested in knowing how the device handles the you're-not-supposed-to-parallel-small-conductors issue.

this doesnt parallel them. Its two 2P3W plugs to a 3P4W receptacle, designed to be plugged into two receptacles on different phases. The box in the middle contains circuitry and a contactor / relay to keep it from operating in a dangerous mode (one plug disconnected, both inputs on same phase, etc)

Please explain how the neutrals supplying the 30 amp receptacles are not placed in parallel by this box?

I agree that it does parallel the neutral, but it's not premises or portable wiring under NEC purview (which stops at the receptacles).
 
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LawnGuyLandSparky

Senior Member
Maybe code oughta address marinas... and require a variety of receptacle configurations instad of the hodge-podge currently permitted where the marina owner decides what they want to provide...
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
this doesnt parallel them. Its two 2P3W plugs to a 3P4W receptacle, designed to be plugged into two receptacles on different phases. The box in the middle contains circuitry and a contactor / relay to keep it from operating in a dangerous mode (one plug disconnected, both inputs on same phase, etc)
I was talking about the two grounded conductors, one in each cord.
 
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