sub panel vs equipment disconnect

Status
Not open for further replies.
tadavidson

tadavidson

Senior Member
Location
Georgia
Occupation
Electrical Contractor
An xray machine in a chriopractors office needs a single phaase 240v 100 amp circuit to feed it. I have been asked to mount a 100 disconnecting means. Will this circuit and panel be classified as a sub panel requiring 4 wire or will 3 wires suffice?
 
I think you are asking us questions we could never answer for you since we are not there. I would think it would be a branch circuit if anything. An EGC should be present. Check equipment installation instructions.
 
The way you described the situation, you only need three wires. They are two phase conductors and the EGC. I would like to know if you are certain it is not a 240/120 single phase, and that the equipment does not need a neutral. If you need a neutral, then you need four wires, and you have to keep the EGC and the neutral separated.

Since the extra disconnecting means you are using is just a switch, and not a fused switch or a breaker, then it does not constitute a ?sub panel.? The circuit is a ?branch circuit? all the way back to the panel. It is not a ?feeder? from the panel to the disconnect, and a ?branch circuit? from the disconnect to the equipment.
 
The unit doesn't have any 120v loads. The salesman/company rep I spoke with said "we always just mount a small panel with a 100 amp breaker and then hard wire it to the machine with SJO." I told him If i use a panel with any extra spaces that someone will ultimately land in it for recepts or something and therefore it would be a sub panel and need 4 wires.
I agree the intended or spoken use would be branch circuit, but was uncertain about the application due to the breaker and possibility mentioned.
My local supplier doesnt have a single phase safety switch 100 amp non fused. or 100 amp indoor disconnect. Thanks for the Feed back.
 
Also check out 400.7 on the use of flexible cords. I believe this installation would require that the cord be connected using a plug and receptacle and not be hard wired.
 
I read it as you. The connection to the unit will be performed by the machine supplier. I was told they would connect it with sjo. It wouldn't be the 10,000th time I heard of equipment installers....we've been doin it that way for years. Article 517? Would anyone care to speak if a Chiropractors areas fall under this art.
 
Status
Not open for further replies.
Top