×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Hazardous Location Brigde Crane

Hazardous Location Brigde Crane

Hazardous Location Brigde Crane

(OP)
We are installing a 3 ton explosion proof bridge crane here at our plant.  The area is rated Class I Division 1 Group D and Class II Division 1 Group F & G.  According to the NEC the cabling should be rated extra hard usage.  This would be like SO cable.  We would like to use a festoon system with flat ribbon cable because it has less problems when coiling and uncoiling.  Is there a flat ribbon cable made rated for extra hard usage?  What others are doing for bridge cranes in hazardous locations?

Thanks

RE: Hazardous Location Brigde Crane

Have you talked with the crane supplier?  Seems like an "explosion-proof" bridge crane would have to take the power delivery system into account.  Normally the festoon cable system is provided as part of the crane, at least in my experience.  

It would be best to have the crane supplier's fingerprints on the explosion-proof rating all the way back to your fixed power disconnect switch.  

RE: Hazardous Location Brigde Crane

(OP)
Yes, the crane vendor is looking into this.  In previous installations, the vendor has installed flat ribbon cable with the same outer covering as SO cord, but the flat ribbon cable does not say it's rated extra hard usage.  Like I questioned before, what's the rest of the industry using in hazardous locations for bridge cranes?

Thanks

RE: Hazardous Location Brigde Crane

In my experience the SO cable power feeds seem to work fine.  The supports for the cable have to be aligned properly and maintained.
In additon to power cable I think your going to need an air line to pressurize the big enclosures and at least two wires to operate the breaker that feeds the crane.  
Enclosures on the crane are pressurize slightly over atmospheric.  If any on them are opened a pressure switch is used to shut down all power to the crane.

RE: Hazardous Location Brigde Crane

(OP)
Thanks for the information, but at our plant we've experienced problems using SO cords for festoon systems.  The cord doesn't lay nice and flat like ribbon cable and then becomes tangled up.

For the hazardous location, we are installing the controls in the equipment room rather than up on the crane.  Our previous experience with having the controls on the crane is that it becomes very laborious removing all of the bolts used for explosion proof enclosure.

We have used the Bebco style pressure switches on other equipment when can't purchase something rated for the hazardous environment.

Thanks again

RE: Hazardous Location Brigde Crane

I have a question reqarding your crane.
What requirement is there for your mechanical componet design under this hazardous classification. The festooning for example has sliding metal components. Is there a code that determine what designs/materials you select?

What about the wheels, is there a code that determines if the crane wheels are suitable for this environment

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources