Equipment as an assembly

[Newtechemmanuel]

Hello all,

Problem: I have an PLC enclosure that was built by students many years ago. When moving buildings the inspector so happened to look into our PLC room and see a company doing the installation. They failed the inspection and had to close the lab. Once the lab was closed the building was cleared for occupancy, the whole building was cleared. So the issues the inspector laid out were a simple fix. The enclosure below is the one I am referencing.

Solution: My solution buy some new UL listed enclosure (15) with viewing windows with an integral depth of 8 inches. It was so simple that I thought I was dreaming. Found a placed called Dixie Electric Controls( really nice people)

New Problem: All of the equipment is UL listed including the new enclosures, but once I put the PLC unit into the box and both networking controllers inside the box, will I need to have this box re-certified by UL as an assembly. I'm wondering since everything is already UL listed the enclosure is listed and labeled for the purpose of enclosing and providing protection against live parts.

The Servo Motor and Power Flex and 1hp motor will all stay outside the enclosure.

 

[retirede]

You didn’t state what code section he cited as a violation, but I think the best approach might be to ask him what he will accept.

 

[Newtechemmanuel]

The original violation was super obvious; and for the life of me I don't know how I let them install it that way. But anyways as you can see I have equipment that can be energized not protected against accidental contact, Furthermore, I have open conductors hanging free in the air the conductors need to be protected against damage and lastly the enclosures did not bare a NTRL sticker so I had to purchase ones that were UL rated @ $22,270.53. Once I purchase the new cabinets everything that Is on the face of the original cabinet ( pic above) will be inside the cabinet with the exception of the servo motor, 1 hp motor and Power Flex drive.

My question is once I put all of the external equipment ( PLC, Comms, Network) will I have to have this inspected as an assembly. I wouldn't think so since the purpose of this enclosure is to hold equipment or route wires. I mean it's sort of like a buying a handy box enclosure, I can install a switch or receptacle or dimmer or motion sensor but the inspector isn't going to require it to be UL listed as an assembly. I'm just wondering if anyone has run into this before?

 

[kwired]

Is this an instructional lab? Information given sort of suggests that. If anything make it so that it is something portable and with main connection via cord and plug, then it is not part of premises wiring and probably not really subject to AHJ inspection any more than any plug in household appliance would be.

That said this probably not exactly OSHA application either, but at same time if instructional lab, maybe good idea to still consider such requirements for safety and training purposes anyway. I'd say at very least none of those exposed conductors is a good idea if they are operating over 50 volts to ground.

 

[Newtechemmanuel]

Is this an instructional lab? Information given sort of suggests that. If anything make it so that it is something portable and with main connection via cord and plug, then it is not part of premises wiring and probably not really subject to AHJ inspection any more than any plug in household appliance would be.

That said this probably not exactly OSHA application either, but at same time if instructional lab, maybe good idea to still consider such requirements for safety and training purposes anyway. I'd say at very least none of those exposed conductors is a good idea if they are operating over 50 volts to ground.

Yes it's an instructional lab setting. It's our PLC lab and the inspector was just walking around the first floor trying find the soda machine. He just so happens to walk past our PLC lab and the fellas doing the install. I guess he got inquisitive and started looking around and bam $7,000 worth of UL certifications, $4,000 worth follow up inspection, and $22,000 worth of new equipment. All for a freaking $1.50 soda. Crazy thing is I agree with everything the inspector said, I'm all about safety and student safety is paramount in my book. I wish I would've caught this before installing; As a matter of fact, I told them to wait until we have building occupancy and then install everything, but nooooo!

 

[kwired]

Yes it's an instructional lab setting. It's our PLC lab and the inspector was just walking around the first floor trying find the soda machine. He just so happens to walk past our PLC lab and the fellas doing the install. I guess he got inquisitive and started looking around and bam $7,000 worth of UL certifications, $4,000 worth follow up inspection, and $22,000 worth of new equipment. All for a freaking $1.50 soda. Crazy thing is I agree with everything the inspector said, I'm all about safety and student safety is paramount in my book. I wish I would've caught this before installing; As a matter of fact, I told them to wait until we have building occupancy and then install everything, but nooooo!

There may been some things you could done to improve safety, but this guy needs stuffed into a 24x24x8 cabinet (nothing larger than that) lock the cover and throw away the key.

Like I said, I don't think there would be much hazard if all the over 50 volt to ground conductors are inside appropriate enclosures. The PLC - that possibly just the main power supply in a lot of cases, which very well could just have the power supply remotely located from the rest of the PLC The servo controller - might need to be enclosed in a lot of cases.

The VFD and the motor - are fine as long as you use a chapter 3 wiring method for power leads. even flexible cord possibly something you don't get too picky with in this situation, though a chapter 3 method still probably the better thing even in an instructional lab.

The real AHJ of such lab conditions is probably an insurance provider. They may still use some standard such as 70e as a basis for what they allow though.

 

[Newtechemmanuel]

There may been some things you could done to improve safety, but this guy needs stuffed into a 24x24x8 cabinet (nothing larger than that) lock the cover and throw away the key.

Like I said, I don't think there would be much hazard if all the over 50 volt to ground conductors are inside appropriate enclosures. The PLC - that possibly just the main power supply in a lot of cases, which very well could just have the power supply remotely located from the rest of the PLC The servo controller - might need to be enclosed in a lot of cases.

The VFD and the motor - are fine as long as you use a chapter 3 wiring method for power leads. even flexible cord possibly something you don't get too picky with in this situation, though a chapter 3 method still probably the better thing even in an instructional lab.

The real AHJ of such lab conditions is probably an insurance provider. They may still use some standard such as 70e as a basis for what they allow though.

Man you are good that is exactly the size box I bought with the correct depth. I will most definitely take a hard look at chapter 3.
Lastly, Thanks for all the help!

 

[kwired]

Man you are good that is exactly the size box I bought with the correct depth. I will most definitely take a hard look at chapter 3.
Lastly, Thanks for all the help!

Chapter 3 wiring methods are basically raceways and cable assemblies, other than K&T and open wiring on insulators though those are pretty restrictive on what is allowed.

Note flexible cord is in chapter 4 and not 3, so typical SO cord would not be a chapter 3 method, though uses permitted in 400.10 could possibly have some conditions that might allow it, likely being subject to interpretation though, if you want to be strictly following NEC.

 

[tom baker]

Is there a panel shop or system integrator in your area. perhaps they could take your equipment, put it in a new enclosure and put a UL label on it. Maybe they would give you a discounted price.They might be willing to do that as some of your students may end up working for them or they would see the value to the industry and helping you out as you are a training facility. once you get the your label your inspector would be satisfied.