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-   -   Adapting 240V 4-conductor (http://www.diychatroom.com/f18/adapting-240v-4-conductor-180387/)

Richo 05-23-2013 10:27 PM

Adapting 240V 4-conductor
 
Hi All,

I built a portable sub panel for a band using a NEMA 10-50 range plug. This works just fine for them but occasionally they will play a place that has an older 3 prong dryer receptacle.

What would be the proper way to use this panel with a 3 conductor configuration?

Also, could someone shed some light on grounding the neutral bar to the box? Should it be done or not? In my main panel at home the neutral and ground bars are attached to each other and to the panel. When should the neutral bar not be grounded to the panel?

Thanks for your help.

bobelectric 05-23-2013 11:15 PM

Never tie neutral and grounds together on a remote panel as you desribed although all stage hands have done this at one time or another.You need a 4-wire receptacle and plug.

Richo 05-23-2013 11:21 PM

But what do you do when only a 3 wire plug is available? Are you able to drop the neutral?

Techy 05-23-2013 11:24 PM

No, 4 wire is required.

sirsparksalot 05-23-2013 11:26 PM

2 Attachment(s)
Quote:

Originally Posted by Richo (Post 1186190)
Hi All,

I built a portable sub panel for a band using a NEMA 10-50 range plug. This works just fine for them but occasionally they will play a place that has an older 3 prong dryer receptacle.

What would be the proper way to use this panel with a 3 conductor configuration?

I'm a bit confused. The 10-50 is a 3-prong, so it should fit the dryer receptacle.

bobelectric 05-23-2013 11:32 PM

Spark alot,the picture you showed is commonly called a range receptacle. A dryer receptacle has the L shaped prong. Richo make a 30-50 amp cheater cord to get the band going.If you tell the venue they need to run the proper receptacle,maybe they will listen .

Richo 05-23-2013 11:35 PM

My mistake, I meant to say NEMA 14-50.

The NEMA 10-50 is the receptacle on the wall of one bar they play. Bands use it all the time so apparently they are dropping the neutral or ground, or tying them together.

sirsparksalot 05-23-2013 11:47 PM

Quote:

Originally Posted by bobelectric (Post 1186247)
Spark alot,the picture you showed is commonly called a range receptacle. A dryer receptacle has the L shaped prong.

Tis true, Bob, but then a dryer is normally 30a, not 50. I looked up the 10-50, as OP described.

sirsparksalot 05-23-2013 11:51 PM

I guess that's another spot to consider. Is the 3-prong at the bar a 30a dryer, or a 50a 3-prong range?

EDIT: am I confused again? :(

frenchelectrican 05-24-2013 12:01 AM

Quote:

Originally Posted by Richo (Post 1186250)
My mistake, I meant to say NEMA 14-50.

The NEMA 10-50 is the receptacle on the wall of one bar they play. Bands use it all the time so apparently they are dropping the neutral or ground, or tying them together.

That useally not the best move with that set up and I have ran into that situation pretty often when someone try to cheapen up the system like that.

The only safe way is have that bar to run a proper 14-50 receptale / circuit that will take care of netural / ground issue plus some case it will knock down a bit of audio noise as well.

With 120 volts stuff what you have and use the proper portable subpanel that will work just fine with 14-50 set up but a nice gotcha from time to time due some bars I know they will use 208 volts instead of 240 volts due the triphase supply ( there are few case they will use 240 volts triphase that will get ya a suprised so give you a head up use the voltmeter to verify the power before you turn on any expensive items on. )

Merci,
Marc

sirsparksalot 05-24-2013 12:11 AM

Richo, just curious, 240v and 30-50 amps for your equipment? What kind of equipment uses that?

frenchelectrican 05-24-2013 12:20 AM

Quote:

Originally Posted by sirsparksalot (Post 1186282)
Richo, just curious, 240v and 30-50 amps for your equipment? What kind of equipment uses that?

Sirsparksalot.,

IIRC the only major 240 volts load I know some will use is big arse spotlights or large floodlight and that about it. ( only in USA side )

But with more modern LED luminaires that will really reduce the amout of the power useage to the luminaries but for the sound system it will NEVER change at all and it will always be on 120 volts unless you have monster unit which it can blow the wall off the foundation.

Merci,
Marc

Philly Master 05-24-2013 05:59 AM

i think this would be considered a temp setup ...

AllanJ 05-24-2013 06:42 AM

Buy or make cheater cords (with some limitations). Here you want an adapter with a 4 prong receptacle for your portable subpanel and a 3 prong plug (hot hot neutral) to connect with the venue's electrical system. Have a green pigtal coming from your adapter to connect to a known ground.

You may also need cord adapters for other different amperage receptacles. You will need to construct your subpanel for and provide it with a plug for the largest amperage circuit that a venue may provide. For example you may not build an adapter with a 40 amp receptacle and a 50 amp plug although vice versa is okay.

(Your portable subpanel does not have neutral and ground bonded.)

In this situation I suggest just making do rather than tell the venue you need such and such (a receptacle or whatever). You don't want to lose gigs over technicalities.

usair 05-24-2013 08:09 AM

Iwould offer this solution purchase a spa panel with a 50A GFI rated at 6 milliamp trip. Attach a three prong male to the line side ( hot,hot,neutral) and a four prong female to the load of the 50 GFI . Seperate the neutral and ground.


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