Dumb electrical questions...

[Mini-MillX2]

Sorry if this isn't the right place to ask!

I just purchase a Thermal Dynamics Cutmaster 101. (haven't recieved it yet). I wanted to prewire the outlet for the 240 connection. The manaul says it needs an 80AMP breaker and number 6 wire. Is 6 gauge wire adequate for up to 80Amps? I thought it was only good for about 55-60amps?

I also contacted Thermal Dynamics about the outlet and wiring and they said use a 2 conductor with a ground and a NEMA P6 receptical. I can't find anything an a NEMA P6 and doesn't 240 usually use a 3 conductor with a ground? If I knew what the plug/receptical looked like I would know if I really need 2 or 3 conductor. Anyone hooked one of these up recently?

[sparkness]

national electric code sais 50amp for 6 gauge or #6 wire, 100 amps for #4. the Thermal Dynamics Cutmaster 101 draws 67 amps. depending the distance that the wire runs from the main breaker panel will determine what gauge to run. you can get away with #6 for a short run about 100 ft if longer go with #4 you will get the most power from your plasma. welding supply's sell the appropiate plugs and recepticles that you will need

[in2steam]

240 single phase will only have 3 wires, 2 hots and a ground, more often then not this taken from a 3 phase system inside a structure or plant. 3 phase 240 can have 3 or 4 wires and that depends upon how the transformer is wired. Also there can be 240 single phase that is taken from a 480 3 phase system, and that will be a single 240 hot with a neutral(its still hot) and ground(to a Y transfomer), but this is rare and I have only seen it once in a machine.

220(residential) single phase will only have 3 wires 2 hots and a ground.
It sounds like you are using 240 single phase which would only be 3 wires. If you are running 220 volts you should go with the larger wire size as your draw will be higher then at 240.
So when in doubt get a an electrican, as for plug you can get those from grainger or mcmaster, they are more then likely refering to a 6-50, avaliable in premium hence P which is phenolic if memory serves. Some times compaines refer to the P as plug also, its confusing, for the couple minutes it takes to put it into the wall I would just wait till you see it, then head over to the hardware store or supply outfit.
chris

[Perp]

Just as a general reference for all of us amatures around here, where is a good source of guidance on wiring up single phase lines off of three phase boxes. (I have 3 phase and need to add a 125amp single phase sub panel).

Maybe a website or a book. As a last resort I will hire an electrician, but I would like to do as much myself as I can being this is a do it yourself kind of site.

Thanks

Doug

[millman52]

simple volt meter check of your 3 legs of 3 phase should tell you. 1 of the legs should have higher voltage. Don't use that one. If you are going to need 110V from your sub panel you also need a neutral as well as a ground

[Al_The_Man]

If you have a delta supply, you should get the same reading between any two phases, You will not have any neutral.
If you have Star output, then there will be an equal reading between phases but there will be a centre connection tap that may or may not be brought out, you will get 50% reading from any phase to this star point.
If you require a neutral, this would be it, but ideally it should be grounded at the transformer, Check you local service supplier for the correct requirements, as some jurisdictions differ.
Depending on the star or delta, your phase voltage difference could be 208 or 220.
If you need 120vac 1 phase, then it may pay to set up a separate 1 phase transformer, with grounded neutral.
Al.

[Perp]

I already have 110 1ph, I would like to add a sub-panel to be able to add a few more 110 1ph and a couple of high amp 220 1ph. When I look in the inside breaker box there are 3 black wires and one white one. Of the three black wires one has red electrical tape around it, another has blue tape around it, and the third has no tape at all. Someone renting the unit before me has written in permanent marker that " lights - red, outlets - blue". I assume that the white is the neutral as it has its own bar on the side and all of the white wires on the regular 110 1ph circuits are common conected here. If it helps I can take a picture or two tomorrow of the inside of the breaker box. I am not afraid to wire things myself but this looks nastier than a 15 amp wall outlet and I like not being dead. Any and all qualified advise is very helpful and appreciated.

Thanks

Doug

[Geof]

Perp; You might think I am being a wet blanket but I think it may be wiser to get an electrician. You refer to; "Someone renting the unit before me" and this implies commercial property. This suggests the property may attract inspections from people with acronyms like OSHA on their business card. Sometimes it is better to spend a little money upfront to guard against things that might bite you in the future.

[Perp]

Originally Posted by Geof Perp; You might think I am being a wet blanket but I think it may be wiser to get an electrician. You refer to; "Someone renting the unit before me" and this implies commercial property. This suggests the property may attract inspections from people with acronyms like OSHA on their business card. Sometimes it is better to spend a little money upfront to guard against things that might bite you in the future.

Not a wet blanket, more like good advice. I still would like to know how it all works just for my own head, but i think my fire insurance people, landlords, and neighbors would all agree with you, and i will too.

[Geof]

Originally Posted by Perp Not a wet blanket, more like good advice. I still would like to know how it all works just for my own head, but i think my fire insurance people, landlords, and neighbors would all agree with you, and i will too.

Look over the electricians shoulder, discreetly of course. And if he/she seems a nice person ask lots of questions.

[Al_The_Man]

Originally Posted by Perp When I look in the inside breaker box there are 3 black wires and one white one. Of the three black wires one has red electrical tape around it, another has blue tape around it, and the third has no tape at all. Someone renting the unit before me has written in permanent marker that " lights - red, outlets - blue". I assume that the white is the neutral as it has its own bar on the side and all of the white wires on the regular 110 1ph circuits are common conected here. Doug

Doug, Under the code you can run the same colour cables as long as they are identified at termination points, Phases usually coloured Red, Black, blue & Neutral white.
By the way, if you are adding any 1 phase loads, it pays to try to spread the load to retain as much balance as possible between phases.
Al.

[in2steam]

Originally Posted by Geof Perp; You might think I am being a wet blanket but I think it may be wiser to get an electrician. You refer to; "Someone renting the unit before me" and this implies commercial property. This suggests the property may attract inspections from people with acronyms like OSHA on their business card. Sometimes it is better to spend a little money upfront to guard against things that might bite you in the future.

I would be more concerned about people whos card says,
"fire inspector for city of"
they come for one of two reasons, #1 your building is not there any more, need I say more
#2 They are doing a routine state inspection, and even on comerical propterty that might happen even when you are not there....

"electrical/building inspector"

They issue fines, make you rip perfectly good installations, and are in general a pain in the rear.

OSHA generally doesnt worry about supply lines, only machine wiring, unless someone gets hurt installing the wires.

chris