elec question RE 220V outlets

[sparkkky]

I hope you ran a separate #6 cable to each outlet, or else you should swap out the 50A outlets (and breakers) for 40A. IIRC, #6 is minimum wire size for a 50A circuit. )</font>


And the above is not completely true, as #8 THHN to a A/C is alright on a 50A breaker.


BTW I am not up to speed on the tap rule as no one uses it anymore in the real world except maybe in some plants.

 

[VA_Joe]

That is correct. The NEC is all about safety. The purpose of the breaker is to protect the wiring (and structure) from fire. Although there are guidelines as to how many outlets should be connected to a single breaker (for calculated loads) it has no bearing on what you are doing. Your circuit will be under-utilized.

I would worry more about the impact of voltage drops over long runs than anything else (as measured from the service entrance panel to the farthest point). Generally - I wouldn't worry about 50-100 feet. More than that and I would start thinking about moving up to the next size wire. I would also check to see if the welder really needs 50 amps. My Lincoln 220 volt welder is rated at no more than a 20 something amp draw. The instructions, however, specify #8 wire with a 40 amp breaker. Methinks the reason for this is to prevent nusance trips caused by extremely short transient pulses (unlike fuses there is no such thing as a slow trip breaker). If this is the case - then don't worry about wire size - you are already taken care of.

Concerning the piggy back breakers - when doing a new panel installation - they should be always reserved for future electrical upgrades. New installations should be always be sized such that those positions are not initially needed (not by code - just good practice). Otherwise, the addition of even a single new circuit (e.g. a bathroom heater) would require the costly installation of a subpanel (or a new main panel).

This, however, is usually not the case (20 piggybacks in a twenty slot box is not uncommon). Unfortunantly, most home owners (and tract home builders) do not consider electrical wiring to be as important as a nice bathtub. The end result are few "useable outlets" (i.e. bedroom outlets in the center of the walls vice at the two ends); breaker boxes with makes/manufacturers no one has ever heard of (the GC's price break will eventually be made up by the homeowner the first time he has to buy a $30 replacement breaker); and the mixing of lights and outlets on the same 15 amp circuits (so that the lights dim each time a page is printed on the laser printer). But I digress

Since you are already thinking of adding a subpanel - I would make it 100 amps vice 60 to provide room for future upgrades (if the subpanel is to be located next to the main panel - the cost of the wire will be only a few dollars more). BTW - #6 wire in conduit can do 60 amps (it's #6 NM wire that is restricted to 50 amps)

As far as wire box sizes go - the bigger the better. Your knuckles will be your friend.

Hope this helps

VA_Joe

 

[DTCOOPER]

</font><font color="blue" class="small">( You guys scare the crap out of me! Half of my work is cleaning up after do it yourselfers.

You can run a larger cable, like a #4 and tap off of it up to ten foot(need to check my book) then you need to set a disconnect at every plug which will get costly fast.

Best to run dedicated circuits on there own breakers, I will not do it any other way! )</font>

Sparky,
I think you are misunderstanding.. We are not talking about running a larger wire and "tapping from it". We are talking about running a single circuit with mulitple devices.

feeding a circuit of multiple devices, is perfectly legal and safe so lon as teh branch wiring is protected by an overcurrent protection device. Be it a breaker or fuse.

Your saying that a disconnect is required for every device, is extreme over kill. And around here you would price yourself out of work very quickly.

And as far as voltage drop... You would have to have a pretty LARGE shop, before you start worrying about voltage drop. The typical "worry free" run can be 80-100' for 120 volt circuits. Or even longer for 240 volt circuits. However, I can see how wiring a circuit to multiple devices can add up to some long footages pretty quickly though.

I do not recall from your earlier posts if you are planning on running the wire through conduit, or using a NM cable. You may find that it will be cheaper to make you a long extension cord from so 8/3 SO cable and have it to use anywhere, rather than wiring multiple receptacles in your shop..

Daniel

 

[sparkkky]

What I was refering to is using the tap rule like running #3's on a 100A breaker and the branching off to feed more than one machine like in a machine shop.

And yes if you read again a larger wire was suggested.

Now you suggest a long Ext. cord, GEEZ! /forums/images/graemlins/crazy.gif

BTW I have not priced myself out of work yet, life is good and we just got back from a trip to Sturgis.

 

[MikeIA]

</font><font color="blue" class="small">( I sell some small "POLARIS" connectors which in essence are rubber coated distribution blocks. )</font>

Cool...I've seen the big ones for 4/0 and such, but I haven't seen ones for #6. Definately the way to go.

 

[DTCOOPER]

Sparky,
I understand what you were saying as well.. I apologize about the larger wire thing..

Extension Cord - The building (garage) is most likely not that large. If he could get away with a 40-50 foot cord, He could use some 8-3 SO cord and make an extension cord that would work in any area of his shop, or outside his shop for that matter. Again, it is not a permanent installation, but something portable and mobile... Which is what he is looking for. Just another suggestion..

MikeIA - Yes sir, those connectors fly off the shelf llike you would not believe. We them for everything from
10awg- 1000MCM... in all hole configurations from 2-6 holes

 

[VA_Joe]

The 8/3 extension cord is an excellent idea. I don't know why I didn't think of it considering that it's what I do in my garage.

As far as wire length is concerned - my only point was that the size of the garage is not as important as the distance to the next largest size wire (or service entrance). Having a #6 wire attached to a subpanel fed by #6 doesn't do much for voltage drop.

In any case - unless he has a really HUGE welder - the 8/3 extension cord should suffice.

VA_Joe

 

[Inspector507]

Mark,
All I'm going to tell you is what I have in my garage, or what I could do if I wanted to. It all meets code and is perfectly safe.
I have a welder plugged into a 50A outlet supplied with #10 and protected with a 50A breaker. If you look at the NEC® Article 630.12(B), it says I can protect the conductors at 200% for an arc welder.
Now if I wanted to add 2-3 more of those same outlets, I'd run #10 from one to the other on the same circuit and use one at a time. At the most, if I tried to use more than one, I'd trip the breaker which has just done it's job.
I know this may not meet popular opinion, but it meets the NEC® and is safe to do.

 

[VA_Joe]

I would double check on that as I believe Article 630 refers to welders that are hardwired.

 

[Inspector507]

OK.........I double checked.........

<font color="blue"> 630.1 Scope.

This article covers apparatus for electric arc welding, resistance welding, plasma cutting, and other similar welding and cutting process equipment that is connected to an electric supply system.
</font>

I've re-read the whole article and no where does it mention "permanent" or "hard-wired". Maybe your book says something different than mine.

Reprinted with permission from NFPA