Rail-Mounted Traveling Crane - Runway Conductor Disconnecting Means

[Wekstrom]

2011 NEC Article 610.31 Runway Conductor Disconnecting Means:
States the disconnecting means shall be "within view of the runway contact conductors".
Are they stating that the disconnect shall be within view of the runway contact conductors at the point of attachment to the power source wiring(i.e the beginning of the runway)?

If so, how is it possible to comply with this requirement when our runway conductors are over 200ft long?

 

[GoldDigger]

2011 NEC Article 610.31 Runway Conductor Disconnecting Means:
States the disconnecting means shall be "within view of the runway contact conductors".
Are they stating that the disconnect shall be within view of the runway contact conductors at the point of attachment to the power source wiring(i.e the beginning of the runway)?

If so, how is it possible to comply with this requirement when our runway conductors are over 200ft long?

I would interpret it to mean either that there is some point along the runway conductors which is in line of sight to the disconnect or else that there is a line of sight specifically between the disconnect and the point of attachment. Clearly, with the switch at ground level you cannot have it in line of sight to every point along the runway.
What is you concern with having it within view of the attachment end? You can have an emergency disconnect which can be actuated from anywhere along the runway combined with or separate from the disconnect required by this section.

 

[steve66]

I would interpert that as meaning its in view from somewhere along the runway. So someone could walk along the runway and find the disconnect.

In other words, the disconnect is NOT located in some electrical room or somewhere else in the plant, where service people would be unable to find it.

The requirement for a lock attachment on the disconnect keeps others from turning the disconnect back on while someone is working on the crane.

 

[Wekstrom]

Rail-Mounted Traveling Crane - Runway Conductor Disconnecting Means

GoldDigger,
Thank you for your response.
We have several existing crane installations with the disconnecting means located within site of the point where the power source is connected to the runway conductors (i.e. the very beginning of the 250ft run). We believe that this satisfies the NEC Article 610.31. An outside crane inspection company has inidcated
that additional regulations/rules exist which appear to indicate that the disconnecting means shall be within site at any point along the runway. This would require
us to install several additional disconnect switches, in series, along the entire 250 ft length of runway (a very expensive modification) . If this were true, do you have any thoughts on the logic behind this?

 

[Cow]

I would say multiple disconnects would make it nothing but more confusing than one single disconnect.

I can just see someone from maintenance asking if they have to lock out all the disconnects now or just one to work on the track....

The KISS method should apply here.

 

[GoldDigger]

GoldDigger,
Thank you for your response.
We have several existing crane installations with the disconnecting means located within site of the point where the power source is connected to the runway conductors (i.e. the very beginning of the 250ft run). We believe that this satisfies the NEC Article 610.31. An outside crane inspection company has inidcated
that additional regulations/rules exist which appear to indicate that the disconnecting means shall be within site at any point along the runway. This would require
us to install several additional disconnect switches, in series, along the entire 250 ft length of runway (a very expensive modification) . If this were true, do you have any thoughts on the logic behind this?

Adding to steve66 response, I would say that a single disconnect located at the origin would be all that is required by NEC, since this disconnect is intended to be for maintenance on the equipment. The locking provision means that it does not have to be in continuous view of someone at any point along the runway. Indeed if I could see a closed disconnect from where I am on the runway, it does not tell me whether any other disconnects may have been opened or by whom or why.The premise for LockOut-TagOut (LOTO) is that there is a single associated disconnect and everyone working on the supplied circuit will have to coordinate through that central point.
If the crane inspection company is looking for more, perhaps as an emergency shutoff rather than a maintenance disconnect, I think it could be better handled by a remote trip than by series switches. Just so there is a procedure around resetting the remote trip!
To the extent that these are additional rule or regulations outside the NEC, you need to get them to point you to those codes to see just what they say.

 

[Wekstrom]

Rail-Mounted Traveling Crane - Runway Conductor Disconnecting Means

Steve66
Thanks for your feedback. This information has been helpful and will serve me well as I discuss the issue further with the servicing contractor.

I would interpert that as meaning its in view from somewhere along the runway. So someone could walk along the runway and find the disconnect.

In other words, the disconnect is NOT located in some electrical room or somewhere else in the plant, where service people would be unable to find it.

The requirement for a lock attachment on the disconnect keeps others from turning the disconnect back on while someone is working on the crane.