Any electricians out there ?
Can anyone answer my question about wiring a 60 amp circuit ?
I am wiring my shop to do some metal fabrication and blacksmithing and have two welders, a plasma cutter and a ceramics kiln. I only use one of these tools at a time but I don’t want to have to unplug every time I change from using the mig welder to say the plasma cutter. And I want to be able to use the tools anywhere in my 40 x 36 Ft shop.
I want to install three to four outlets on one branch circuit using Nema 6-50 receptacles. I would like to use 6-2G Awg wire which is rated for
55A. A little less than the breaker I want to use.
Can I use a 60A breaker for the 6-2 wire? One of my loads, a ceramics kiln requires 48A and would trip a 50A breaker.
Is there a better way than using large wire nuts to pigtail the receptacles onto the branch circuit ? It seems like I have seen some crimp type connectors
and there are also those split bolt connectors.
thanks
Chris
Replies
Chris-
First things first, I am NOT an electrician. But when I had my new heat pump installed, the electrician that did the wiring had to make a junction in the 60A backup heat circuit. He used disconnect boxes. Why? He explained to me that there are special crimp connectors required on the heavy guage wire and that wire nuts are prohibited by code. Thus, the disconnect boxes were cheaper than an actual junction box with the required crimp connectors, while still complying with code. Apparently, special tools are needed for these crimps too . . . . .
This doesn't really answer your question except to say that big wire nuts on a circuit of this amperage are (in my understanding) prohibited by code. Furthermore, your proposal to wire 4 receptacles to one 60A breaker is a violation, I think. The code doesn't care about what you will actually plug into the circuit, it is only concerned with the POTENTIAL to plug too much into that circuit. As you propose, the POTENTIAL exists that you could plug in all 3 appliances at once and overload the circuit. Again, this is my understanding of the code, but I'm not an electrician.
Hopefully someone more knowledgeable will post more. Were it me? I'd call my friendly electrician, tell him what I want, and pay him merrily when he is through. Adding a 15A receptacle is one thing. But you're getting into some major juice with these circuits.
1. AWG #6 can carry 60A, depending on the insulation used. Check the table in the NEC for specifics.
2. However, you can't put a 50A receptacle on a 60A branch. The branch must be 50A.
3. Also, on a 50A branch, you can only install one receptacle.
4. A possibility would be to install a 60A subpanel, with 3 or 4 50A branch circuits, one per receptacle. As long as you're using only one receptacle at a time, the subpanel feeder breaker won't blow. There may be a issue with this from a strict feeder loading capacity problem (see section 220, etc of NEC for guidance), but at least it would be safe.
5. These receptacles should have screw terminals, don't they? I don't understand the pigtail reference.
Edited 4/23/2002 7:46:17 PM ET by BarryO