240v Wiring ?

[planeflyer21]

Howdy all.

This afternoon I wired up a plug onto a lead smelting pot, following the instructions on the plug box: green to ground, white to neutral, black to hot. Looking from the wire to the back of the plug, green on the bottom, white on the left prong, black on the right right prong.

Looked at the plug on the lathe and it was the same: white on the left prong, black on the right prong.

Never one to leave well enough alone, I pulled apart the 50A outlet for the welder. Lo and behold, it is wired so that the black (hot) wire goes to the left prong, white on the right prong.

My question is this: with two hot wires coming to the outlet, does it matter which one is grounded? Does it matter how your plugs are wired?

I've always been under the impression it makes a difference.

 

[pdentrem]

240 has 2 hot wires while 120 has only 1 hot & 1 neutral. 240 plugs are not polarized unlike the 120 ones. At least that is my understand of that. The 3 phase at work is a different animal again if it has a neutral or not.
Pierre

 

[John Hasler]

white to neutral, black to hot.

Wait a minute. This is a 2-wire (plus ground) 240VAC circuit? If so you have no neutral. You should have two hots (black and red, usually) and green ground.

 

[jim18655]

If you used a 3 conductor cord then the only thing you need to worry about is the location of the green ground. The black and white don't matter. You did use a 240v plug - right? That would have the blades horizontal, for lack of a better description. The receptacle is the same way, doesn't matter which side is white or black. If you used non-metalic cable put black tape on the white to designate it's live. If in conduit you should have pulled two colors for the hot wires.

 

[ARKnack]

Doesn't matter. Both lines are hot. Left or right, both the same. As long as green wire goes to the green screw. A white neutral is not required if you do not have 120vac requirement. You normally can not find Red/Black/Green power cord. You should use a black felt marker and paint the white wire black indicating that it is a hot wire. I hope you are using a proper 240vac plug and not a 120vac plug.

 

[TOOLMASTER]

it will flip 60 times a second all by itself ;-)

 

[jim18655]

Seconds

 

[planeflyer21]

Thanks everyone!

Don't need to start something on fire. I'd never hear the end of it.

Wait a minute. This is a 2-wire (plus ground) 240VAC circuit? If so you have no neutral. You should have two hots (black and red, usually) and green ground.

My apologies. That was the terminology on the Pass&Seymour legrand box.

Jim18655 and ARKnack, yes, I'm using a 6-15 plug.

 

[Wreck™Wreck]

240 has 2 hot wires while 120 has only 1 hot & 1 neutral. 240 plugs are not polarized unlike the 120 ones. At least that is my understand of that. The 3 phase at work is a different animal again if it has a neutral or not.
Pierre

A polarized 110 wall plug assures that the "neutral" is connected to the grounded (for want of the correct term) leg, you may have noticed that many modern hand tools do not have a distinct ground connection, also alternating current at the US standard 60 hz changes polarity every cycle, or 120 times per second.
3 phase AC also has no polarity, it merely alternates 120° between each leg.

 

[stupoty]

A polarized 110 wall plug assures that the "neutral" is connected to the grounded (for want of the correct term) leg, you may have noticed that many modern hand tools do not have a distinct ground connection, also alternating current at the US standard 60 hz changes polarity every cycle, or 120 times per second.
3 phase AC also has no polarity, it merely alternates 120° between each leg.

Yeah like wreck says it might be polerised Live Neutral if it's a ground referenced neutral system you should read 240volts across live and earth and 0volts across neutral and earth. easy way to check for reversed wiring. Most installations in the UK only switch the Live so it's quite important its round the right way.

Stuart