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-   -   Adapter for 2 15-20amp to 1 30amp? (https://www.forestriverforums.com/forums/f218/adapter-for-2-15-20amp-to-1-30amp-15211.html)

SlowerThanU 07-29-2011 06:39 PM

Adapter for 2 15-20amp to 1 30amp?
 
Hello Everyone,

I plan to use my new Grey Wolf 19RR at race tracks in the pits when I'm doing track days or racing. The pit areas usually have plenty of 15-20amp outlets for things like lighting, fans and tire warmers but very rarely do they have a 30amp plug for an RV. Has anyone heard of or made a pig tail that plugs into two separate 15-20amp circuits to create a 30amp rated outlet? This would be similar to the concept of pairing two 2000 watt generators. I've searched but can't find anything like this although in theory it should work. Any guidance would be greatly appreciated.

Ovair 07-29-2011 10:13 PM

Well, there's this Fretz Enterprises Online Store
which isn't exactly what you want, but it seems similar. It at least uses the same sort of idea (combining two sources into one.

caper 07-29-2011 10:22 PM

It cannot be done.

SlowerThanU 07-29-2011 10:38 PM

Ovair's post proves it can be done, there just isn't a readily available product for my application. This would be no different than the cheater cables already available to combine a 20 and 30 amp circuit like the one above or linking two generators together to increase available amperage.

18CrewDually 07-30-2011 12:24 AM

This cheater box does the same as Ovair's post. Cheater Box

But this is taking electricity from 2 different lines. What your looking for won't accomplish anything because the 2 outlets are the same line which is only rated at 15amp. So, in that case it can be done but your NOT gaining anything except a good chance of blowing the tracks breakers.

Herk7769 07-30-2011 07:03 AM

I suppose if you were to find a 220 VAC 30/50 amp outlet in the shop area used for welding or a large air compressor, you could make a pigtail the converts that outlet type to a 30 amp RV socket.

(I must add in all fairness that this is way beyond my abilities and could be dangerous as H$%^)

As to hooking up two 15 amp duplex sockets via some magic and getting 30 amps?
Sorry, No. ;)

leencharlotte 07-30-2011 07:04 AM

If I am not mistaking the reason it will not work is the voltage not the amps. A50 amp plug is 2 110v plugs=220v. A 15,20 or 30 amp is 110 each, combining the 20 and 30 gives you 50 amps and 220v combing 2 15/20 amp plugs will also give you 220v. Your trailer is only rated for 110.

For this to work I would imaging you would need two converter boxes in your trailer, each with a dedicated line to run certain appliances.

KyDan 07-30-2011 07:14 AM

IF the track actually has 20 AMP circuits and you are the ONLY person on a given
circuit you can probably use a basic 30 amp to 20 amp adapter and run your roof AC
but not much else at the same time. If you need an extension cord it should be
AT LEAST 14 ga and it must not be very long. I have successfully ran my roof AC both
in my driveway as well as my sister's house on a 20 amp wall outlet.

You can usually find these at WalMart or any RV parts counter or camp store.
(Mine is round but looks similar to this)
https://www.pplmotorhomes.com/parts/r...ords/10231.gif

kbrown1075 07-30-2011 07:26 AM

Please look up AC / Aleternating current. I don't want to get to technical but you have a sine wave (AC power). One side of the wave goes above (+) and one goes below (-). When you are using 110 VAC you are only using half of the sine wave. The other half is being used on the other "leg". So, if you have a 220 VAC, 50 A connection, half of your breakers are using the + side of the wave and the other half of your breakers are using the - side of the wave. Hence, you have all 110 VAC at your outlets. In most residential breaker panels starting at the top of one row, the breakers alternate "legs" as they they go down. So, if that made any sense, if you took two 110 VAC plugs and "piggy backed" / parrellel connected them to a 30 A RV plug and pluged them in, you best make sure BOTH outlets are on the same leg in the breaker panel AND THAT THE WIRING IS 30 Amp rated, which I can gaurunty will not be the case. Why would you wire a 15 or 20 Amp outlet for 30 Amps.

So the answer to your question: Heck no!! Don't even try it. You will distroy your electrical/ electronics equipment real quick!!!!! Or worse yet, hurt someone.

caper 07-30-2011 07:27 AM

It cannot be done because as stated you are not only increasing the amps but also the voltage. If you do not think this is the right answer talk to an electrician.

SaskCampers 07-30-2011 08:27 AM

You will have a very bad day if you try that and may very well hurt someone. One thing you could do is add a seperate input to the trailer to power a few outlets in the trailer for coffee etc. like someone else here did. And use the 30A input just to power your air unit. That way you won't hurt anyone. Of course if you just plug into one duplex outlet chances are you still only have one 15 amp cct and will still pop the breaker.

SlowerThanU 07-30-2011 09:53 AM

Ok, admitting that my knowledge of AC isn't what it used to be I might be barking up the wrong tree here. The concept wouldn't be to plug into the same outlet, but outlets on different circuits as previously stated. Just like the 20+30=50 cheater boxes that have already been linked to. I'm waiting to hear back from a buddy of mine who's an electrician, I'm sure you older/wiser guys will end up being right.

Herk7769 07-30-2011 11:28 AM

Quote:

Originally Posted by leencharlotte (Post 121893)
A 15,20 or 30 amp is 110 each, combining the 20 and 30 gives you 50 amps and 220v combing 2 15/20 amp plugs will also give you 220v. Your trailer is only rated for 110.

For this to work I would imaging you would need two converter boxes in your trailer, each with a dedicated line to run certain appliances.


Lee,

Unfortunately this is not the case.

The feed line from the circuit panel determines what can be done at that outlet. On a regular duplex outlet there is ONLY 110 VAC available and it is shared by the two sockets. Since the 110 VAC is a single phase, no amount of "piggybacking" will give you 220 VAC. The 220 VAC must come from the panel in the form of two opposite phase 110VAC lines from a "married" or tied double breaker.

Additionally, with a single 15 amp breaker on the 110VAC branch there is 15 amps TOTAL available on the entire branch (shared among all outlets on that branch).

So if there are 3 duplex outlets on the branch (6 sockets total) the entire draw from all 6 outlets can only add up to 15 amps without blowing the breaker.

Hope this helps and does not confuse. :)

leencharlotte 07-30-2011 12:01 PM

Quote:

Originally Posted by herk7769

Lee,

Unfortunately this is not the case.

The feed line from the circuit panel determines what can be done at that outlet. On a regular duplex outlet there is ONLY 110 VAC available and it is shared by the two sockets. Since the 110 VAC is a single phase, no amount of "piggybacking" will give you 220 VAC. The 220 VAC must come from the panel in the form of two opposite phase 110VAC lines from a "married" or tied double breaker.

Additionally, with a single 15 amp breaker on the 110VAC branch there is 15 amps TOTAL available on the entire branch (shared among all outlets on that branch).

So if there are 3 duplex outlets on the branch (6 sockets total) the entire draw from all 6 outlets can only add up to 15 amps without blowing the breaker.

Hope this helps and does not confuse. :)

Gotcha! What if the plugs are different breakers would it be the same?

Herk7769 07-30-2011 12:49 PM

Quote:

Originally Posted by leencharlotte (Post 121944)
Gotcha! What if the plugs are different breakers would it be the same?

Man my head hurts. :o

I am no electrician but I am going to take a stab at an answer.
I would definitely run this by someone QUALIFIED to make an informed answer as well. It will be YOUR camper that melts down into a puddle of aluminum if you get it wrong.

Electrically, I believe it should work (IMO) HOWEVER The protections afforded by the "tied" 220 VAC breakers will not be available. For example if someone plugs in a drill on one leg of the circuit somewhere in the bay, you could overload BOTH circuits and cause all kinds of problems.


Now for how I think it MIGHT work:

IF you use two different 15 amp branch circuits AND they are from the SAME PHASE you should get a maximum of 30 amps 110 VAC from the two legs. you would connect both black hots from the dual pigtail to the hot on your 30 amp RV socket and both white neutrals to the neutral on your 30 amp RV socket. Twist the copper ground wires together and connect to the ground lug on the 30 amp RV socket. The load (what ever it is) will be split equally between the two feed lines. For example if the camper is pulling 20 amps; 10 amps will come from each circuit breaker as long as the camper is the ONLY thing on both branches.

The phases on a panel ZIG ZAG down the panel and alternate every other breaker. Example: Left side: Breaker #1 phase A; Breaker #3 phase B; Breaker #5 phase A again.

So you would use Breakers #1 and Breaker #5 to tie together.

IF you make a mistake and use a circuit from the OTHER phase in the panel, when you throw the second breaker there will be a light show like you have never seen before. You will have a DEAD SHORT of 220 volts at the 30 amp RV socket which will cause quite a fire. :eek:

caper 07-30-2011 01:54 PM

It will not work by using two 110 circuits.You will have a live short. You will blow the breakers at the race track and maybe not before it causes a fire. If and when you do try to jump 2 circuits together make sure your life insurance is up to date.

KyDan 07-30-2011 02:06 PM

Quote:

Originally Posted by leencharlotte (Post 121944)
Gotcha! What if the plugs are different breakers would it be the same?

NOPE!
IF the breakers are on different "legs" of the transformer that feeds them,
you will wind up with 20 amp 240v and you will fry your electronics in your
trailer. IF you connect 2 different legs to the SAME hot wire you have
a dead short and it will go BANG
If they are on the same leg you get 120v and maybe a tad more than
20 amps but you'd be breaking all sorts of electrical codes.

Like I said-- IF they are actually 20 amp 120v outlets AND you are the
only guy on a particular circuit, you CAN run your roof AC with the adapter
I show below.
My roof AC actually uses just a tad less than 15 amps. I ran it one day
and night at my sisters house when temps where 102 that afternoon.
I did not kick her breaker until she turned on the light in the garage.
That little shop lite was enough to push me over the line and trip the breaker.
We shut off the lite and let the breaker cool and ran the AC the rest of the
day. I can't swear it was a 15 and not a 20 but her house is 35 years
old and I bet it was just 15.
You say the track has 20 amp outlets, I say you will be OK.

Beyond that unless you strike up a real good friendship with the track
electrician and can con/talk/bribe him into installing a 30 amp 120v
breaker for you this is your only option in my opinion.

37 years industrial electrical maintenance and 10 years RVing says so.....

kbrown1075 07-30-2011 02:16 PM

There is definetly too many variables to even attempt this on a known breaker box at your OWN house never mind getting access to the panel and figuring out how it is wired at the race track. IMO, it is time to come up with a much safer plan. Maybe a quiet generator?

Herk7769 07-30-2011 02:58 PM

Quote:

Originally Posted by caper (Post 121964)
It will not work by using two 110 circuits.You will have a live short. You will blow the breakers at the race track and maybe not before it causes a fire. If and when you do try to jump 2 circuits together make sure your life insurance is up to date.

Well, I did say I was not a qualified electrician and you may be more qualified to answer this question. Again, this is an open forum and anyone, qualified or not, can post stuff.

However IMO, I believe you are not correct, so long as the 110 circuits are common phased. ;) Obviously connecting two 110 VAC circuits out of phase will result in a 220 VAC short since there is a path to ground on the negative side of the sine wave on the opposing "hot". Two common phase hots will be "hot" (at the same potential) at the same time so there is no path to ground.

This is actually easy to check. Open the circuit breaker panel and put a meter across the hot outputs of two adjacent 110 VAC breakers. The potential is 220VAC and connecting them will result in a dead short.

Then check the potential across the breaker right below that one (the common phased one) and you will see there is NO voltage reading (open circuit). Connecting them will not cause a short. QED :thumbsup:

Txcamper 07-30-2011 09:39 PM

One thing that hasn't been discussed is that fact of tying legs from two different circuits together would allow back feed of electricity up one of the circuits from the other should only one breaker blow. Just a thought.


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