SO cord without attachment plug

[steve66]

A company is installing a xray unit in a doctors office. The xray unit has a a part that moves. This part has 2 SO cables coming out of it. The xray installer ran these two cables through a hole in a cover plate on a wall box. In the wall box, he butt spliced the SO cord to THHN wire. The THHN runs in conduit and connects to the xray unit.

The local inspector says SO cord can't be used as a substitute for fixed wiring. He wants attachment plugs placed on the SO cords. The THHN would then terminate on receptacles (nonstandard). (This isn't normal 120V power, its part of the Xray unit circuitry).

I think 400.7 (A) (10) allows the SO cable for connection of moving parts, and 400.14 allows the cable to run through a cover with a bushing. I am also worried that we are adding plugs to the manufacturer's equipment design (ie, we are modifying the equipment).

The inspector doesn't buy my argument. Please give me your opinion. Do you think the receptacles and plugs are required, or not?

Steve

[ October 24, 2003, 05:26 PM: Message edited by: steve66 ]

 

[hbiss]

Re: SO cord without attachment plug

SO cord can't be used as a substitute for the fixed wiring of the structure. (400.8) This is not a case of fixed structure wiring however. You are correct in citing 400.7(A)(10) and 400.14. Rather than just passing through a J box cover, even with bushings, there needs to be a strain relief. (400.10) Use listed compression fittings. Otherwise I can't see what is wrong with this.

 

[ryan_618]

Re: SO cord without attachment plug

Assuming that there is a means of disconnect that complies, I also would not have a problem with it.

 

[david]

Re: SO cord without attachment plug

hbiss:

How is this not part of the fixed wiring of the structure? Wouldn?t the wiring before the equipment disconnect belong to the structure?


Did the manufacturer intend these SO cords to be connected to some kind of disconnect?

[ October 25, 2003, 01:07 AM: Message edited by: david ]

 

[hurk27]

Re: SO cord without attachment plug

Many tanning beds come from the factory with So cord attached to connect to a disconnect. and even Says so in there instructions?
If cord were not alowed thed why would the NEC require protection for them when run into a outlet box?

400.14 Protection from Damage.
Flexible cords and cables shall be protected by bushings or fittings where passing through holes in covers, outlet boxes, or similar enclosures.

 

[david]

Re: SO cord without attachment plug

I think I miss spoke I re-read the post and I now see that Steve said this moving part was part of the xray equipment not the xray equipment.

Good night:

 

[hbiss]

Re: SO cord without attachment plug

How is this not part of the fixed wiring of the structure? Wouldn?t the wiring before the equipment disconnect belong to the structure?

Because the SO cord is not run within, in raceway, or attached to the structure.

 

[david]

Re: SO cord without attachment plug

Ok here goes. First I already said that I miss spoke on this. But why isn?t the SO cords long enough to reach the xray machine. It seems the installer extended the xray secondary equipment wiring using THHN in conduit in the wall. This wiring method is usually part of the structural wiring. The junction point between the SO cord and the THHN usually would require a means of disconnect. This junction makes this a gray area and I am not in a position to say the Inspector was wrong. Had the SO cord run from the xray camera, projector, I am not sure what you call this secondary equipment to the xray machine and only used the conduit as a means of support I don?t think we would be having this conversation.

 

[hbiss]

Re: SO cord without attachment plug

Had the SO cord run from the xray... and only used the conduit as a means of support I don?t think we would be having this conversation.

Correct because then it would be prohibited.

400.8 Uses not permitted.
(4) Where attached to building surfaces.
(6) Where installed in raceways, except as otherwise permitted in this code.

 

[steve66]

Re: SO cord without attachment plug

hbiss:

I think you are right on track. The installer can't run the SO cord through conduit, so he splices it in a wallbox and runs THHN back to the control panel.

I was trying (maybe not hard enough) to point out that this wiring is part of the xray equipment as opposed to a 120v branch circuit. Although the installer says the wires will be 120 volts, I really have no way of knowing what voltages, currents, or signals occur on these wires.

Since there are about 8 wires here, there would have to be at least two receptacles. If the xray unit were turned on with one or both the plugs unplugged, I have no way of knowing what would happen. If only one were plugged in, the voltage could backfeed to the other plug and the prongs on an attachment plug would be hot!!

I am stuck in the position of having an inspector requiring something I consider unsafe. I guess I will have to try to convince him that the receptacle idea isn't a good one again.

Steve

 

[earlydean]

Re: SO cord without attachment plug

They make both male and female cord caps. But, if the X-ray machine is permanently attached to the structure, then, IMO, there is nothing wrong with attaching the cords via cord connectors to the J-box.

 

[caj1962]

Re: SO cord without attachment plug

instead of the articles already quoted i would use tis one to turn down your instalation

660.4 Connection to Supply Circuit.
(A) Fixed and Stationary Equipment. Fixed and stationary X-ray equipment shall be connected to the power supply by means of a wiring method meeting the general requirements of this Code. Equipment properly supplied by a branch circuit rated at not over 30 amperes shall be permitted to be supplied through a suitable attachment plug cap and hard-service cable or cord.
(B) Portable, Mobile, and Transportable Equipment. Individual branch circuits shall not be required for portable, mobile, and transportable X-ray equipment requiring a capacity of not over 60 amperes. Portable and mobile types of X-ray equipment of any capacity shall be supplied through a suitable hard-service cable or cord. Transportable X-ray equipment of any capacity shall be permitted to be connected to its power supply by suitable connections and hard-service cable or cord.

 

[steve66]

Re: SO cord without attachment plug

So caj1962 is going to side with the inspector!! That's OK, I really just want the installation to be as safe as possible. I'll even admit I may be wrong in thinking an attachment plug is a really bad idea in this case.

However, I will continue to argue my case. The first problem with quoting article 660 is 660.1: This article covers all Xray equipment operating at any frequency or voltage for industrial or other nonmedical or nondental use.

This is definately a medical installation.

In addition, 660.4 is for "Connection To The Supply Circuit", and this is more internal xray equipment wiring.

Steve

 

[hbiss]

Re: SO cord without attachment plug

I was trying (maybe not hard enough) to point out that this wiring is part of the xray equipment as opposed to a 120v branch circuit.

Yes, I did surmise that and perhaps I also should have emphasized that point also. This is not a supply circuit. The supply for the x-ray unit is connected to the control panel on the wall. Therefore, in my opinion, 660.4 would not apply.

Another point, if the machine is UL listed as I'm sure it is, the SO cord and method of connection was accepted. I'm only surprised that the manufacturer didn't provide a punched plate for a box and strain reliefs (or did they?). Did the installation instructions detail how to install these cables?

 

[steve66]

Re: SO cord without attachment plug

hbiss,

Apparently, the company that made the unit is out of business, and the installer says the instructions don't show any diagrams of terminating the SO cord.

Good point about the UL listing though. I wonder if there would be any way to get anything from the listing that shows how to terminate the SO cord on this unit.

Steve

 

[caj1962]

Re: SO cord without attachment plug

Sorry i missed the part about being in a healthcare facility, but try this one for the inspector.
517.75 Equipment Installations.
All equipment for new X-ray installations and all used or reconditioned X-ray equipment moved to and reinstalled at a new location shall be of an approved type.
Just for the record most of the xray equipment installers I have dealt with were very knowledgable about there equipment. It is when the sales guy takes an old unit in on trade and then works a deal with the dentist down the road that things get a little crazy. They end up piecing the equipment together and just making them work.

 

[hbiss]

Re: SO cord without attachment plug

Apparently, the company that made the unit is out of business, and the installer says the instructions don't show any diagrams of terminating the SO cord.

Hmmm. Well I still stick to my story but I assume now that this is a used machine? If that is the case the fact that there is no plate or strain reliefs provided and the installer made up his own raises a red flag. I wonder then how the SO cords were originally supposed to be connected? Have you looked at the literature yourself to see if what the installer is telling you is correct? I would want to see for myself. Could be that he is trying to bury the issue by saying that that is the way it's supposed to be done. A schematic or wiring diagram would indicate splices or connectors, and if there were connectors and they were cut off for some reason when the machine was removed (this thing could have been around the block a FEW times) they will need to be replaced to maintain any approvals. Would it have been possible that the cords previously were run directly to the control panel without the THHN/raceway due to a different setup of the room?