4 pin twist lock plug wiring question

[ozzy214]

I'm trying to make a adapter to wire up my Genny to my plasma cutter. The plasma is 3 wire and the Genny is 4 wire 20 amp twistlock. I would like to wire the twistlock to a 3 wire range plug, since the extension cord for the genny is wired with a 3 pin range plug for plugging into my shop 220.

Anyone have a schematic for this or explain it to me, be much appreciated. I already know the range plug 2 v;s is hot and the middle prong is ground, but not sure on the twistlock which is hot and ground.

I can obviously fire the Genny up and probe the terminals while its running, but my luck will shock myself.

Also do you think a 5500 watt genny is enough for the plasma? According to the manual output is max 40 amps and input is 19.2 amps. Its a harbor freight inverter model. So im thinking the 20 amp output on the genny is enough, but probaly when the air compressor kicks on, will have to stop using the plasma till its done running right?

 

[Norcal]

A locking ("Twistlock" is a registered trademark) plug has marking on the terminals what they go to, the neutral is silver & the grounding is green.... (the neut. is not needed on a 240V load).


A genny is not going to like a overload of a compressor trying to start w/ a large load already in use.

 

[theoldwizard1]

A locking ("Twistlock" is a registered trademark) plug has marking on the terminals what they go to, the neutral is silver & the grounding is green.... (the neut. is not needed on a 240V load).


A genny is not going to like a overload of a compressor trying to start w/ a large load already in use.

My 5kw generator runs my 2hp "oiled" compressor just fine. Minor rpm drop when compressor kicks on.

Between the 2 of them you really need ear protection !

 

[ozzy214]

Ok that helps, but it is a nos plug. And the only color I can discern is green. Cant tell if the others are brass or silver. It does have letters next to the pins. Any ideas?

 

[Norcal]

Ok that helps, but it is a nos plug. And the only color I can discern is green. Cant tell if the others are brass or silver. It does have letters next to the pins. Any ideas?

What are the letters?

 

[gatchel]

Maybe this will help:

http://en.wikipedia.org/wiki/NEMA_connector

 

[cat3306]

A locking ("Twistlock" is a registered trademark) plug has marking on the terminals what they go to, the neutral is silver & the grounding is green.... (the neut. is not needed on a 240V load).


A genny is not going to like a overload of a compressor trying to start w/ a large load already in use.

I had to laugh at your statement saying you don't need the ground for 240... ALL of my 240 items MUST have a ground or they WILL NOT run. Besides that fact you WANT a ground on 240 just incase you get lit up.

 

[where2]

Letters should be X, Y, W, and G.

Presuming you have an L14-20P you are attempting to wire:
X and Y are across from one another like East and West are on a compass.
G and W are across from one another like North and South are on a compass.

G has the extra 90° bend on the tang.

Looking at the back of the plug like you are looking at a compass, if you orient:
G = North, then
Y = West, X = East
W = South.

X and Y are your two legs of hot. W = neutral, G = ground.

That info is according to the Marinco L14-20P I grabbed out of my garage for reference.

 

[pattenp]

??? Norcal said a neutral was not needed for 240. Who's laughing now?

I had to laugh at your statement saying you don't need the ground for 240... ALL of my 240 items MUST have a ground or they WILL NOT run. Besides that fact you WANT a ground on 240 just incase you get lit up.

 

[wyliesdiesels]

I had to laugh at your statement saying you don't need the ground for 240... ALL of my 240 items MUST have a ground or they WILL NOT run. Besides that fact you WANT a ground on 240 just incase you get lit up.

Where did Norcal say a ground is not needed?? He's an electrician by the way, so expect that u just stirred up a hornets neat!!

Im also curious why u think a 240v device wont run without a grounding connection? That doesnt make sense! A 240v device gets power from the 2 hot legs NOT the ground wire!

 

[pattenp]

cat3306, now that we have beat up on you, welcome to GJ.

 

[LG63]

Is there only one twist lock? Most generators this size also have a 3-wire 240V/30A too.

Edit: My mistake, it's usually a 125V/30A

 

[pattenp]

The locking outlet is usually a L14-30 120V/240V 30A.

Is there only one twist lock? Most generators this size also have a 3-wire 240V/30A too.

Edit: My mistake, it's usually a 125V/30A

 

[where2]

The locking outlet is usually a L14-30 120V/240V 30A.

Strangely, not all the 5500W generators have 30A twistlocks. I've got a 5500W with only a pair of 20A breakers and an L14-20R. It has always baffled me, but I have found enough L14-20P plugs in my ReStore to last me a lifetime.

 

[pattenp]

Not to take a poke at your generator, but the Harbor Freight 4000W gens even have a L14-30R.

Strangely, not all the 5500W generators have 30A twistlocks. I've got a 5500W with only a pair of 20A breakers and an L14-20R. It has always baffled me, but I have found enough L14-20P plugs in my ReStore to last me a lifetime.