Electricians - Have an electricity question again

The code requirements are in the NEC code book which you can get at a good bookstore for like $40. The "Ugly's" reference book you can get at Home Depot or Lowe's for less $ should have what you need as well. A lot safer to buy the correct reference materials.

Pete C.

I know that my Math is correct, so just curious about the wiring requirements. I have looked in one of my books that mentions 6 guage for 50 amps, they just don't mention 60 amps and higher, so I'll have to keep digging.

The current capacity of wire depends on the insulation and if it is in a conduit or not. If it is in a conduit the number of wires and size of the conduit also makes a difference. Try Rec.crafts.metalworking. There are some electricians in that group.

Dan

My old 1999 copy of the NEC says 55 amps max for #6 copper, and I doubt if any other version allows higher current. The NEC tables list higher currents for higher temperature ratings, but these higher ratings can only be used for derating allowance, never to actually increase ampacity above the 60 degree C rating. You however need to comply with all aspects of your local code *and* have that verified by a licensed electrical underwriter (inspector) in writing, if you want your insurance to remain in effect after the installation. I suggest you call an inspector before you start the job and discuss what you want to do in advance, so that you only need to do the job once and pay for one inspection. The inspection will be dirt cheap compared to the cost of an uninsured fire, probably well under $100.

watching this since its start, but still don't understand the problem.

Here in the UK we run 240 volt for domestic, and 415 for Commercial premisses.

BUT if a home owner requires a 415 volt supply for running Commercial grade equipment it can be applied for , and if costs met, accomplished.

Not too clear on the physics, but I believe all electric feeds here are in 3 phase 415 volt, giving a huge amount of amps. For instance you can get 3 phase 415 volt at 125 amps per phase.

Surly you can have this as well if there is a problem?

Also why not do a proper job, and put all low power on one supply, and all high power on a separate dedicated supply?

Please point out if I've ,missed something as this seams to be very easy to solve, but ignorance is bliss at times ;-)

Vaughn

Virtually all US residential service is 220 single phase, centertapped to 2 110vt cicuits. Most are 100 amp capacity, though newer construction now generally are 200 amp service.

Most residential areas dont have 3 phase even available on the pole, simply two wires and a neutral passing by.

I inquired about 3 phase service for my home shop..and the power company quoted me $15,000, and would have to use some rather complicated phase shifting transformers to get it to me.

Most..not all..but most commercial areas do have 3 phase..generally

208vts..with the higher 440 available, and of course..the higher voltages available via special transformers etc on request.

Which is why those of us who use 3 ph industrial machine tools build rotory phase converters etc, simply because we have no other options availble to us.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

I have a 150 amp service panel.

How can you say, "do a proper job", that is what I'm trying to do.

Many thanks it all makes sense now.

Me I only use the little DIY stuff at home so no problem, but I can see the cost and phasing problems can add to a real question of DO I need this or not?

Again thanks for the help

ignorance is bliss at times ;-)

Need I explain any more ;-)

I did post on the other board and also call my local city inspector. This is what I have decided and posted on the other board.

Ok, I just got off the phone with a local city inspector to verify. He said that between 50 - 60 amps, 6/3 NM-B is fine. For over 60 amps up to 100 amps, then they mandate you run 4/3 NM-B wire. He did say also, if running through my basement ceiling, the holes in the joists must be a mininum of 1 1/2 inches from the bottom. I guess that is incase you finish the ceiling and nail/screw drywall in.

So I will be putting in a 70 amp breaker and running 4/3 NM-B to the new breaker panel in the garage.

My pleasure.

As you can see from the link to my home shop...I built a rotary converter rather early one..and not running 3ph machinery is no problem for me. Well...my current RPC is only rated at 5 hp..so when I start up the big Clausing..with its 7.5 hp motor..I have to run the milling machine..as its 3ph motor adds to the power "generating" capacity.

However..I do have a 10hp RPC nearly finished, simply because I aquired a mint mint mint Airco PhaseArc 350 mig machine..3ph and it wont run on the 5 hp RPC with any wire larger than .026.

With the breadboarded 10 hp RPC running..I can burn .045 wire in spray transfer mode quite handily. And reverse the Clausing lathe from full speed.

So we do manage to make work arounds..if we are serious..but most of us do envy you with your 3ph at the breaker panel

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3