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Anyone familiar with prefab addition wiring?

Posted By: petey_c

Anyone familiar with prefab addition wiring? - 11/03/14 01:01 PM

Okay, I got a call from a customer I've known for a few years. His second floor has some issues. Fixed the first couple no problem. The third was the reason I'm writing. (okay, keyboarding) No power to one circuit. Power at the breaker, but disappears between the panel and the first device. Traced the cable back to an exterior wall. While I'm figuring out how to re-run another circuit the HO asks me to take a look at some taped up wires in the ceiling of the master bedroom. I undo one of them and it's a splice for the second floor wiring. Shouldn't these splices have remained accessible? If not for the HO, I would've been there all day. Pics are at ElectricalPhotos.com
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/03/14 02:52 PM

Prefab? You mean this addition came in on a truck? (modular premanufactured building)

Amp does sell an NM connector made for the purpose that can be concealed or even fished.

http://datasheet.octopart.com/208169-1-AMP-datasheet-14548063.pdf

You are right, splices normally need to be in a box and accessible.
Posted By: petey_c

Re: Anyone familiar with prefab addition wiring? - 11/04/14 07:31 AM

The HO said it was a prefab. I don't know if that meant the whole second floor came as one or several pieces. He wants to get rid of those connections and put them in a splice box. He'll paint the cover to match the ceiling and get the cover as flush as possible. Thanks for the info.
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/04/14 08:00 AM

Nobody ever got in trouble doing things the right way.

The Amp splice is legal but I think we all agree a splice in an accessible box is better.
It these are just flying splices without a box it needs to be fixed.
Posted By: ghost307

Re: Anyone familiar with prefab addition wiring? - 11/04/14 06:08 PM

Those AMP connectors are UL Listed to be installed without a box; but they still need to be accessible.
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/04/14 07:36 PM

Originally Posted by ghost307
Those AMP connectors are UL Listed to be installed without a box; but they still need to be accessible.


That is not really true

They come under 545.13

Quote
545.13 Component Interconnections. Fittings and connectors
that are intended to be concealed at the time of on-site
assembly
, where tested, identified, and listed to applicable
standards, shall be permitted for on-site interconnection of
modules or other building components. Such fittings and connectors
shall be equal to the wiring method employed in insulation,
temperature rise, and fault-current withstand and shall
be capable of enduring the vibration and minor relative motions
occurring in the components of manufactured buildings


The installation instructions say
Quote
B. Building Site and Dwelling Site
The separate modules of a building or
dwelling assembled on location are to
be connected elec
trically by the
simple plug-in connection (including a mechanical latch)
of mating pairs thereby providing circuit continuity.
The connected pairs may or may not be fastened in
place. The connected pairs may or may not be
concealed by the installation
Posted By: ghost307

Re: Anyone familiar with prefab addition wiring? - 11/04/14 10:26 PM

When my double-wide was set up they told me that these were used to connect the 2 units together electrically. There was a removable drywall panel in a closet that allowed access to clip them together after the units were in place.

I was told that the panel couldn't be permanently patched in afterwards because the connecteors had to stay accessible in case they needed to be repaired or replaced.

Concealing them was okay just as long as they could be gotten to at a later date.
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/04/14 11:26 PM

The instructions and the code are pretty clear unless you have a local restriction.
For a while Amp was even marketing these for retrofits in regular 1&2 family dwellings but that was stopped in 99 or so.

They were seen as a way to fix that old "burned up TW wire in the ceiling luminaire" problem. They said you could splice on a piece of NM-b and shove it up in the ceiling then install an old work ceiling box. They used 334.40(B) to justify it.

Quote
(B) Devices of Insulating Material. Switch, outlet, and tap devices of insulating material shall be permitted to be used without boxes in exposed cable wiring and for rewiring in existing buildings where the cable is concealed and fished. Openings in such devices shall form a close fit around the outer covering of the cable, and the device shall fully enclose the part of the cable from which any part of the covering has been removed. Where connections to conductors are by binding-screw terminals, there shall be available as many terminals as conductors.



Someone looked into it and decided these particular devices were only approved in manufactured homes, leaving open the question, what does 334.40(B) really apply to?
Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/05/14 01:51 AM

The debate went thru up here also regarding using these devices. We had conflicting answers from the 'higher-ups'.

It was 'yes you can use it for 'old' work' on Tuesday, and by Thursday...it was 'NO, unless it is within the factory that fabricates mfg homes.'

A few ECs thought that this device was the greatest thing since sliced bread; then they saw the cost, and the official "NO".

Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/05/14 01:54 AM

We are getting an increase in pre-fab, modular homes in the recovery from hurricane Sandy. I have not seen any of these Tyco connectors used.

All in all, I have not heard of any issues.

Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/05/14 03:22 AM

I may still have a couple of these around here somewhere. When that debate was going on in the 90s I asked Tyco/Amp for some samples. They sent me 3 but one of each type so there was not a matching set.
Posted By: sparkyinak

Re: Anyone familiar with prefab addition wiring? - 11/05/14 03:45 AM

Here's the problems with prefabs, modulars, etc. They are built in an "engineered controlled environment". As such, the code does not apply. Just like toasters, blenders and such. The NEC does cover RV's and such in an "ECE", the codes do not necessary apply. Some may call BS on me but go ahead, I can take it
smile
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/05/14 05:41 AM

I agree we inspect the installation of manufactured homes (the connection to the service, Grounding electrode system, the tie downs etc) but we don't really inspect the home itself. It is an engineered assembly.

They always see lots of modifications and additions but I am not sure I have ever seen a permit for it.
Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/05/14 08:21 PM

A 'pre-fab' (fixed in place mobile home) requires permits for the electric service, and HVAC that is field installed. The actual 'unit' is not inspected. Bldg requires permit for tie-down, skirting, stairs/landing and the pad. Plumbing requires water & sewer connections.

Modular homes require the same, plus any work in the grade level and exterior. We do inspect the splice points, and any field modifications that may be done.
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/06/14 03:15 AM

True modular homes are very rare around here. You can pay a crew to stick build you a house cheaper than you can truck in a compliant one.
Just about the time these factory guys got a 150 MPH "truck" house approved, we bumped it up to 170MPH.
Block, steel and concrete are king.
Posted By: sparkyinak

Re: Anyone familiar with prefab addition wiring? - 11/06/14 06:44 PM

However if the wiring in a prefab is altered and unless your are a factory rep, it need to meet NEC, state, and local ordinences
Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/07/14 01:55 AM

sparkyinak:

You are 100% correct.
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/07/14 07:13 AM

I think the problem is, if these are in a "park" the neighbors will never complain so these "additions" just happen. They do not have public roads inside the fence so you don't really get much of a chance to drive by for a look.

There are a few gated "foo foo" parks with HOAs that will keep a tight reign on the owners but most are just a free for all. The park owner might raise your rent if you add on tho.
Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/07/14 02:55 PM

Greg:
Here we have a few 'mobile home parks'; chassis mounted dwellings. All that is required for these is a service, and HVAC (CU only), and assuring the chassis is bonded. The 'services' are feeders from a meter and main disco, and the GEC is at that location. The parks for the most part are well maintained by the landlords.

One is a nightmare. Old, and what I refer to as 'the wild west'.



Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/07/14 08:39 PM

All of our parks are old. They were zoned out of existence 30 years or more ago. The ones we have were grandfathered in and most date back to the end of WWII and the 50s.
Some of the units in them are almost that old but they are all George Washington's hatchet (New head and the handle was replaced a few times). Very little is original except the "can". They all have "cabanas", auxiliary buildings, roof overs and lots of interior renovation/repair.
Posted By: HotLine1

Re: Anyone familiar with prefab addition wiring? - 11/07/14 10:33 PM

Just for a laugh, the nightmare has a unit that can be slid into a pickup bed, but...last time I was in there it was balanced on 3 55 gal. drums. 30 amp branch circuit, 10/3 UF laying on the ground from the disco, and one real scary guy inside.

A proliferation of lean-tos, metal awnings, and who knows what else. A fun place for the zoning guys!!
Posted By: gfretwell

Re: Anyone familiar with prefab addition wiring? - 11/08/14 01:29 AM

I have some pictures of some pretty funny stuff going on out west. I understand what you mean. They should get extra credit for UF. I see Romex as often as not on vacation out there.
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