Modular Homes

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jm1470

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I got a call from a customer about wiring a modular home to be honest I have never done one of these. He was going to send me over the plans. Does anyone know what is included and what of the electrical I am responsible for.
 
jm1470 said:
I got a call from a customer about wiring a modular home to be honest I have never done one of these. He was going to send me over the plans. Does anyone know what is included and what of the electrical I am responsible for.
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The terms of modular homes, prefab, mobile, manufacturered are often used loosely so it would be hard to tell. The modular home I did was all wired except for tying in a jb in a closet where the two sections came together. We also had to put the service on the house and wire the a/c unit.

That was a long time ago and I think they were called modular homes. :smile:
 
A true modular home comes in sections on a flatbed trailer, unlike what the salespersons try to say that a doublewide or triplewides are. If it has a frame with axles attached, it's a trailer. They usually have connection points where each module ties together. The one I done the factory sent a crew out with it to tie everything together, and all I had to do was build the service to feed their panel.
 
Modulars are pretty easy, from an electrician's standpoint. The list of things you need to do are normally as follows:
  • mount interior and exterior lighting fixtures and fans, since they are normally shipped sitting on the floor under where they go.
  • Build a service, with disconnect, and pipe to the already installed subpanel.
  • Wire any wells, septic pumps, outbuildings, etc.
  • Completely wire any basement that the home might sit on, however the homeowner wishes it to be done. A 3-way is already factory wired at the top of the basement stairs with a tail (or empty ENT) hanging down.
  • Connect the outdoor a/c unit
  • Plug together any of the Tyco/Molex connectors, if the house installers didn't do that already.
  • Pull the battery tabs on the smokes. Wire in a basement smoke to existing upstairs smokes. There's a factory tail hanging for that purpose.
  • Connect the CATV and Phone home runs. There's normally just a tail hanging for each, under each jack.
  • Do the service and water line grounding and bonding.
  • Troubleshoot everything. Almost never will the factory wiring on any of them be "perfect".
 
mdshunk said:
Modulars are pretty easy, from an electrician's standpoint. The list of things you need to do are normally as follows:
  • mount interior and exterior lighting fixtures and fans, since they are normally shipped sitting on the floor under where they go.
  • Build a service, with disconnect, and pipe to the already installed subpanel.
  • Wire any wells, septic pumps, outbuildings, etc.
  • Completely wire any basement that the home might sit on, however the homeowner wishes it to be done. A 3-way is already factory wired at the top of the basement stairs with a tail (or empty ENT) hanging down.
  • Connect the outdoor a/c unit
  • Plug together any of the Tyco/Molex connectors, if the house installers didn't do that already.
  • Pull the battery tabs on the smokes. Wire in a basement smoke to existing upstairs smokes. There's a factory tail hanging for that purpose.
  • Connect the CATV and Phone home runs. There's normally just a tail hanging for each, under each jack.
  • Do the service and water line grounding and bonding.
  • Troubleshoot everything. Almost never will the factory wiring on any of them be "perfect".
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Good list Marc. Also, in Alabama the POCO will allow the service drop on the side of the modular, but not on a mobile home.

I did two modulars and they both had problems at the feed to the water heaters. The factory guy failed to install the wirenuts properly and they melted and shorted to the shell.
 
ohm said:
Good list Marc. Also, in Alabama the POCO will allow the service drop on the side of the modular, but not on a mobile home.
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Same here, but 9 times out of 10, the factory wired panel is sufficiently far enough inside the home that you need to subfeed it. They seem to wire them as a subpanel, regardless, but do normally ship the bonding jumper inside the panel in case you need to use it.
 
mdshunk said:
Same here, but 9 times out of 10, the factory wired panel is sufficiently far enough inside the home that you need to subfeed it. They seem to wire them as a subpanel, regardless, but do normally ship the bonding jumper inside the panel in case you need to use it.
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True, don't know why they place the SE panel on an inner room. Makes you have to place a MB near the meter. But all in all these were tight as a drum and very high quality. My inspector was very impressed.
 
Modular gas stations are quite simular too, the two halves are tied together with a piece of flex with all of the circuits for the other half in it. I actually wired a couple for a factory that makes them. The local inspector comes out and checks them at rough in and trim out. Both halves are temporarily connected together and every thing is tested. Even the service is already built since each of them are custom ordered. The only thing that is not prewired was the power and controls to the pumps.
 
I love doing modulars. They are quick neat easy money. The panel full of breakers is usually supplied with the service but noone ever deducts that from the price of the service change. Everything is an extra and as Pierre said the basement usually needs to be wired. After doing the service , Basement, oil burner,tweaking problems I usually walk away for about 8k. Quick easy clean work.
 
Not sure if the "NY Cow" sees the same as we see in lower NY, but the panels are not installed with the modulars here, they are generally installed by the EC. I have yet to see one located somewhere other than an outside wall, if not in the basement. There are generally many "tails" left hanging in one corner of the basement.
 
there is a difference between prefab housing like what pierre is talking about and modulars or mobile homes that come in on a trailer and generally get set up on piles of some sort. With mobile homes / modulars the system in the home itself is usually a complete system with panel and all.

Make sure there is a frame bond somewhere on the beams.
And make sure their water heater breaker is off until they get a water supply. No need to burn out that element prematurely
 
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mdshunk said:
Plug together any of the Tyco/Molex connectors, if the house installers didn't do that already.
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Be aware that not all those connections will be in the basement. The ropers at the factory love to scatter them all over the structure. Sometimes, they plan on putting them in the walls or inaccessible attic, so the crew that places the home on the foundation must know about them.... but rarely care to remember them. Sooooo, ol' Sparky shows up, and 2 circuits don't work no matter what you try. :mad:

T&M at this point....

Pierre C Belarge said:
Not sure if the "NY Cow" sees the same as we see in lower NY, but the panels are not installed with the modulars here, they are generally installed by the EC. I have yet to see one located somewhere other than an outside wall, if not in the basement. There are generally many "tails" left hanging in one corner of the basement.
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Every one I've done has the panel mounted to plywood, and fastened to the floor joists. I only need to unscrew it, allow it to drop down and anchor it to the wall. Build a service to it, and done.

A/Cs, electric stoves, dryers, etc. are too big a load for the Tyco connectors, so those HRs (if they're on the other 'side' of the home from the service) will have a long enough coil of NM that needs to be run to the panel.


As stated before, they can always be shipped out with factory mis-wires. You never include troubleshooting and fixing problems in your initial price. You just can't predict that, so it needs to be stated in your contract that it's strictly T&M for that.
 
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I have no BEEF with modulars and I have done quite a few of 2 section and 4 section all that have been shipped for basements.
All of them were prewired other than the homeruns which were coiled up under the house long enough to reach the panel.

The panel was not only Included but in the section that contained the kitchen which had the most circuits which were prewired and landed in the panelwhich was coiled up under the house.
Most fixes were usually minor in nature and additional smoke/co alarms were required by the townships involved.

Installing exterior fixtures at 75 a clip supplied with the house
 
my home is a modular (stick built). there were four j-boxes at one end to tie the two halves together. The crew installed:

furnace
water heater
AC
Service (on the side of the house)
4 lights, 1 smoke and 1 recept outlet in basement.

its neat how the tuck everything between the floor joists including the 200A panel, which all drop down for the basement.

Last year i did a manufactured (built on steel frame). rural setting.

I put new mast, new meter base, 200A disco on pole. Ran conduit UG to home and attached to panel.

no inspections, POCO approval only.
 
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