ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
AreMetal Ladders Ever OK For Electrical Work?
by HotLine1. 01/22/18 07:31 PM
Photocell
by twh. 01/22/18 05:06 PM
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 11 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Medical Trailor #77491
06/15/01 09:46 AM
06/15/01 09:46 AM
C
cinkerf  Offline OP
Member
Joined: Dec 2000
Posts: 84
Pittsburgh, Pennsysvania. ...
A medical trailor is going to be transported to our Firefighters Training Academy. It will be used for testing for 4 days and then taken away. It will come equipped with a 60 amp. 120/240V. 60A. 4W. power cable and attachment cap. A 4W. receptacle will be installed near a subpanel to provide power. Is a ground rod required?

Frank (cinkerf)

2017 / 2014 NEC & Related Books and Study Guides
Re: Medical Trailor #77492
06/15/01 11:43 AM
06/15/01 11:43 AM
M
Mike  Offline
Member
Joined: Feb 2001
Posts: 62
Does the medical trailer have a panelboard?
If it does have a panelboard then I would consider it a structure. Which would lead to Article 250-32, etc., requiring a ground rod. If it doesn't, then I would consider the trailer as portable equipment. Which wouldn't require a ground rod.

[This message has been edited by Mike (edited 06-15-2001).]

Re: Medical Trailor #77493
06/15/01 12:37 PM
06/15/01 12:37 PM
A
Anonymous
Unregistered

The metal shell of the trailer must throughly and solidly bonded to the EGC. You should test the resistance and find it to be low (<2 ohms). If it isn't bonded properly, then I see the need to get it correctly bonded. I don't see the need for a ground rod. A ground rod doesn't make a dangerous trailer safer.

I'm also assuming that the trailer will have a steel jack that would provide a path to earth if lightning strikes the trailer.
The trailer really should have metallic contact with the earth for lightning.

I'm assuming that the trailer has a panelboard - but I still consider it portable as evidenced by the fact that it will be rolled away after only 4 days.

Re: Medical Trailor #77494
06/15/01 04:24 PM
06/15/01 04:24 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,344
hmmmm;
we need to become definitional here,

is this a structure ??

is this a mobile home???

is this a camper??

[Linked Image]

Re: Medical Trailor #77495
06/15/01 06:07 PM
06/15/01 06:07 PM
C
cinkerf  Offline OP
Member
Joined: Dec 2000
Posts: 84
Pittsburgh, Pennsysvania. ...
The Medical Trailor does have a panelboard.

Frank (cinkerf)

Re: Medical Trailor #77496
06/15/01 06:54 PM
06/15/01 06:54 PM
A
Anonymous
Unregistered

It's not a structure mainly because it is not erected on site. Yes, a camper could be a good comparison. But I suspect that no one cooks or sleeps in this trailer.

Re: Medical Trailor #77497
06/15/01 09:18 PM
06/15/01 09:18 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,344
to G-rod or not to G-rod , that is the Q.
hmmm;

550-23(a), last sentence refers to 250-32, so does this mean only the disco gets the rod?

while we are on it, what about art 553 , floating buildings ???

Re: Medical Trailor #77498
06/18/01 07:41 AM
06/18/01 07:41 AM
W
WARREN1  Offline
Member
Joined: May 2001
Posts: 176
Greenville, SC, USA
I would consider the trailer as portable equipment since it has a cord and attachment plug. Even though the trailer was probably manufactured to the stringent standards of MHMA and other required standards (which by the way are now a lot stricter than they were twenty and thirty years ago when I bought my first mobile home).
The cord and plug have two phase conductors, a neutral and a ground. The receptacle supplying power to the unit is deemed as grounded and providing a ground return path. Having said all of that, I think I would insure the shell and frame are electrically connected to the ground in the cable. An ohmmeter check should suffice. If your meter is in the truck a couple of hundred feet away then a scrap piece of #10 connected to the frame and to the receptacle conduit should provide a suitable ground path for fault currents. A separate ground rod may set up a situation with circulating ground currents, and may cause additional problems.

Re: Medical Trailor #77499
06/18/01 09:19 AM
06/18/01 09:19 AM
M
Mike  Offline
Member
Joined: Feb 2001
Posts: 62
Read the thread "Carnival Tent" in IAEI BB. It doesn't matter what NEC article we "think" the medical trailer falls under. It's the AHJ's interpretation that counts [Linked Image]


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
lil suzi
lil suzi
Midwest
Posts: 57
Joined: August 2003
Show All Member Profiles 
Top Posters(30 Days)
Admin 21
sparky 15
Potseal 15
Popular Topics(Views)
243,596 Are you busy
180,394 Re: Forum
170,865 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.016s Queries: 14 (0.003s) Memory: 0.9964 MB (Peak: 1.1609 MB) Zlib enabled. Server Time: 2018-01-23 03:55:43 UTC