Subpanel located in Box truck

Reply

  #1  
Old 05-26-08, 08:20 PM
Member
Thread Starter
Join Date: May 2008
Posts: 2
Received 0 Votes on 0 Posts
Subpanel located in Box truck

Hello everyone. I read here all the time and this is the first time I had to ask a question.

My friend has a box trunk that will be used for sprayfoaming houses. The trunk has a variety of equipment installed in it. It will have a Max load of about 80 amps at 240v. I will be making a whip using Hubbell pin&sleeve connectors to create a massive extension cord. This cord will connect the House Main Panel to the Trucks Main panel (subpanel).

Here is the problem. I need to connect the truck to the main panel of a house. Do in need to carry a 4 wire to the truck, keeping the neutral and groud seperated in the subpanel, or can it be a 3 wire, and bonding the neutral and ground in the sub panel.

I pretty sure the answer is to use 4 conductors leaving the neutral and ground seperated, becasue the grounding conductor is not suppose to carry any current.
there will be no common metal between the trunk and the house. Actually, the trunk will be about 60ft away from the house.

I'm trying not to use ground rods for each job site that he will visit.

Thanks everyone,
Jason
 
Sponsored Links
  #2  
Old 05-26-08, 08:38 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,984
Received 35 Votes on 30 Posts
How do you plan to make the connections to the house panel?
 
  #3  
Old 05-26-08, 08:46 PM
HotxxxxxxxOKC's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2006
Location: USA
Posts: 8,044
Received 0 Votes on 0 Posts
Seems like a large liability issue here. Could you not get a generator? I'm sure the homeowners would not appreciate you using 80amps of their service.
 
  #4  
Old 05-26-08, 09:03 PM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Received 0 Votes on 0 Posts
I have no choice but agree with two guy's comment on this one this is pretty serious issue will come up fast.


Some of the homes only have 100 amp service and that really pushing to the limit for safety sake.

And some area which i know few spots the Electrician may refuse to hook up this type of device if they feel the exsting service is not big engouh to handle and with new home construction majotry of the time they are on tempory power until finsh stage then it will switch over to perment power.

80 Amps is alot and you need some ventation as well and lighting that can easly push the limit of some of 100 amp service pretty fast.

If only being used for few hours IMO it will be more festable to use the generator to run the power for the equiment that person have and far less issue with the electrical system in the house espcally during remodeling or new construction stage.

Oh yeah the Pin and Sleeve device are not cheap and if you insteting to use the house power to run this one you will have to get a hold of electrician [ they can able do it in safe manner ]

Merci,Marc
 
  #5  
Old 05-27-08, 11:46 AM
Member
Thread Starter
Join Date: May 2008
Posts: 2
Received 0 Votes on 0 Posts
Each job will have its own complexity in which we will need to provide a solution. He will not be able to bid on job in which there are no feasible power sources that can run his equipment.
I was just looking for the answer to my question, although, I do welcome all comments.
I will rephrase the question.
I have a friend that wants to hook his trunk up to a house that has a 400amp service split to (2) 200amp service panels. One service panel is completely empty, as this will be the panel we will be pulling power from. Can I run a 4 wire while using the Service panel ground, or should I run a 3 wire and use ground rods at the trunk?
I know grounding conductors are not supposed to carry current, so I answered my last question. Since current follows all paths back to the source, I know I canít bond the neutral and ground in the truck either while using a 3 wire with no ground rods.

thanks everyone.
 
  #6  
Old 05-27-08, 12:06 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,984
Received 35 Votes on 30 Posts
Even with the rephrased question I still believe that you have a large liability questions as to whether or not your friend would meet the definition of a "qualified person".

Live panels, empty or not are not the place for untrained persons.

This idea of yours would also require specialized hardware for each brand of panel.
 
  #7  
Old 05-27-08, 12:19 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Received 0 Votes on 0 Posts
You have a misunderstanding of grounding. The 3-wire vs. 4-wire question and the grounding rod question are unrelated. They are part of two different grounding systems.

Use the 4-wire.
 
  #8  
Old 05-27-08, 12:20 PM
mango man's Avatar
Member
Join Date: May 2004
Location: Sw FL
Posts: 2,122
Received 0 Votes on 0 Posts
how do other "spray "contractors do it ?
 
  #9  
Old 05-27-08, 04:19 PM
Member
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,338
Received 0 Votes on 0 Posts
Originally Posted by mango man View Post
how do other "spray "contractors do it ?
My icynene contractor had a trailer with all of the equipment, and a large pickup (1 ton?) with duals carrying a rather huge military surplus diesel generator. 50kW?

They did a good job. Seemed to work pretty well.

Now the floor guys did a good job too, but they left arc marks in the load center, where they took off the cover to attach their alligator clips directly to the main bus! This was despite the fact that I asked them before the job exactly what kind of receptacle they needed, and they could not tell me. The house was empty at the time, and we were replacing the service anyway, so I didn't make a stink. But had I been there to see that, I would have had something to say to them.

Unless you require the homeowner to provide a suitable receptacle, you are asking for trouble. Good luck.
 
  #10  
Old 05-27-08, 06:52 PM
HotxxxxxxxOKC's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2006
Location: USA
Posts: 8,044
Received 0 Votes on 0 Posts
As a homeowner, I would tell this company to get off my property if they asked to use my panel for this. The company should be self sufficient.

Would this company not take a job if the homeowner refused or did not have the service ampacity? Not a good business practice.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: