Machine Main Electrical Feed Breaker

[Walter Wallace]

Asking for comments on the breaker installation in the pictures below. I am trying to find applicable codes covering the obvious problems in the pictures. The wiring to the breaker is two parrallel feeds of 500mcm cable. As you can see in the pictures, the breaker is installed on top of several contactors and a power supply. This installation is on a new machine installed in 2013 in North East Louisiana. I have raised concerns about the installation in terms of future maintenance and troubleshooting of the devices blocked by the main feed breaker. I am also concerned about stress from the way the cable is installed on the breaker itself. I believe there may be bend radius problems with the 500mcm cable. I am a maintenance technician in a plant with a lot of different and older equipment so I don't have a lot of time to research the code.

I would appreciate any and all comments in reference to this post and the pictures below.

Thanks in advance,

 

[meternerd]

Hard to get enough room in most MCC buckets to make nice smooth bends. In most factory wired breaker panels, the bends are VERY sharp and wire sizing is usually smaller than Code. Exempt from the Code, I think. If it works for them.... Breaker lugs are pretty stout on most brands, so I doubt strain is a problem. From the pictures, it doesn't look like a parallel fed breaker. It's set up with a mechanical interlock and it looks like the load is fed from two different sources. If that's the case, that makes room for wiring even tighter. Sometimes in wiring MCC's, you do what you have to do. Just my opinion, though.

 

[Walter Wallace]

Hard to get enough room in most MCC buckets to make nice smooth bends. In most factory wired breaker panels, the bends are VERY sharp and wire sizing is usually smaller than Code. Exempt from the Code, I think. If it works for them.... Breaker lugs are pretty stout on most brands, so I doubt strain is a problem. From the pictures, it doesn't look like a parallel fed breaker. It's set up with a mechanical interlock and it looks like the load is fed from two different sources. If that's the case, that makes room for wiring even tighter. Sometimes in wiring MCC's, you do what you have to do. Just my opinion, though.

Another problem with this installation is that about 6 doors down in the same MCC, the cubicle is almost empty and there is plenty of room for the breaker there without bending wire around. The feed is two parallel 500mcm conductors per phase to cover the current required by the machine. There are not two seperate feeds. I think they spent too much time trying to save on 500mcm cable. In the process they covered up devices that will need to be serviced in the future. The 500mcm cable will be very difficult to move out of the way. This situation could turn into major downtime if not addressed.

 

[jim dungar]

I believe there may be bend radius problems with the 500mcm cable.

For 600V single conductors, the NEC specifies wire bending clearance not wire bending radius. THHN insulation is commonly installed using sharp 90? 'right angle' bends.

 

[Canton]

For 600V single conductors, the NEC specifies wire bending clearance not wire bending radius. THHN insulation is commonly installed using sharp 90? 'right angle' bends.

Usually with tight wire radius like that the manufacture uses DLO cable. Very flexible and easy to work with, has a higher ampacity than THHN also. Its expensive, but does look like you need very much.

 

[petersonra]

It is not pretty.

It is functional.

I see nothing inherently unsafe or in violation of some mandatory code.

 

[ritelec]

It is not pretty.

It is functional.

I see nothing inherently unsafe or in violation of some mandatory code.

I agree.......

it's easy to blame and criticize after the fact.. if there were to be any "blame" I think it might be on who designed the cabinet...
although it looks pretty bad, who ever fed it maybe could have gone straight into the breaker and it may have looked good but would have made it impossible to service the things behind it... so if he was looking to save on 500's .. nope, don't think so.

 

[Walter Wallace]

I agree.......

impossible to service the things behind it.

I understand that, as it is, it is functional and safe. It is impossible to service the devices behind the 500mcm cables. The 500s totally block access to the devices behind them and this is my biggest issue. The 500s are not DLO, they are THHN so bending them out of the way will be very difficult! It's hard for me to believe that blocking access is not some kind of violation?

 

[jim dungar]

It's hard for me to believe that blocking access is not some kind of violation?

Was this equipment built to some type of industry standard, like NFPA79 or UL508A? These both address the 'inside of' a machine control panel.

 

[ritelec]

Violations? Does it make a difference at this point? Can you call the electric police? You're either going to correct it or leave it.

So watcha gonna do?
1. leave it alone.
2. rework feeders and or main.
3. relocate internal "blocked" equipment.

 

[petersonra]

maybe it was originally designed without a main cb and had to be added after the fact.

 

[Walter Wallace]

Look, I'm just an E&I Tech trying to make a living working in a plant. I'm trying to look out for the well-being of myself, my fellow co-workers, and my company. I feel like this situation if left as is, and one of the devices behind the breaker and the 500mcm cables fails, then this will lead to a very difficult and lengthy fix requiring major downtime. This will not be good for anyone. I would like to locate the breaker in the nearly empty cabinet where the vendor who supplied the machine intended for it to be. Obviusly I can't address the situation without everyone buying into the fact that this situation will eventually create a problem. My company's policy on electrical installations is as follows:

2.1 CODES, REGULATIONS, AND STANDARDS

2.3.1 The electrical installation and materials shall comply with the requirements of the latest revision, based on the date of the Contract, of the following codes, regulations and standards, unless amended to higher requirements by the drawings or this specification:

? National Electrical Code (NEC) (NFPA-70, latest version)? National Electrical Safety Code (ANSI C2) (NBS H30)? National Board of Fire Underwriters (NBFU)? American National Standards Institute, Inc. (ANSI)? National Electrical Manufacturers Association (NEMA)? Institute of Electrical and Electronics Engineers (IEEE)? Insulated Cable Engineers Association (ICEA)? National Fire Protection Association (NFPA)? Standards of the Underwriters' Laboratories, Inc. (UL) on equipment, when available.? Federal Occupational Safety and Health Act (OSHA)? Canadian Standards Association (CSA)? Public Utility Regulations? Additional applicable state or local electrical codes

2.3.2 Where the drawings or specifications show requirements that exceed those of the codes, regulations and standards referred to here, the drawings or specifications shall govern.

2.3.3 Interpretations of the above documents shall be as determined by the ?Authority Having Jurisdiction? for enforcing the code or approval authority.

2.3.4 All equipment shall be capable of being installed and operated in full compliance with the latest edition of the Code of Federal Regulations CFR 1910, Subparts R and S, Occupational Safety and Health Administration, without requiring modifications. Applicable OSHA Safety Standards include, but are not limited to:

1910.261 Pulp/Paper and Paperboard Mills
1910.95 Noise Exposure
1910.147 Control of Hazardous Energy (Lockout/Tagout)
1910.212 Machine Guarding
NIOSH-Lifting Ergonomic Considerations

2.3.5 All equipment supplied must comply with all county, state, and federal regulations and codes in effect as of the date of purchase. For locations with no applicable local building codes, the Uniform Building Code (UBC) shall apply.

2.3.6 All equipment and materials installed shall be certified for the seismic zone specified in the Scope of Work. The Contractor shall furnish and install additional supports when required to comply with seismic requirements.

2.3.7 In the event of conflicting requirements between the above Standards and this specification, the Contractor shall refer such conflicts to Owner for clarification prior to proceeding with the work.

 

[petersonra]

Moving it will lead to an even longer period of time while the machine is down.

Maybe include some kind of remedial action for the next time you have a scheduled shutdown.

If I were going to do something I might be inclined to just take it out altogether and put in fused or CB disconnecting means outside of the enclosure.

 

[Barbqranch]

Without seeing the whole panel, it looks to me like it would be easier to move the timers.

 

[69gp]

Just to understand better is this the elevator control unit located in an elevator machine room?. Here in MA you need to have an elevator mechanics licence to work on anything associated with the machine that controls the elevator. I have my journeyman's and Masters and it will not cover me to work on the "Machine". We are only responsible to bring power to the unit, 110 volts for lights and fire alarm wiring for recall. That's a big liability if something should go wrong.

steve