Prefabrication

[JJWalecka]

I?m curious who utilizes prefabrication to increase profits? I like the idea of Quality prefab if done efficiently.

Feedback is welcome

JJ

 

[dreamsville]

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Not sure what u mean by prefab pertaining to running electrical circuits? :-?

 

[charlietuna]

I worked for a company for eight years that actually had a prefab shop of four men - and it was very sucessful! These men were handicapped electrical workers for one reason or another. The shop specialized in high rise condo buildings. I ran two large jobs for them and once i realized the advantage of ordering prefabricated assemblies - it really cut a lot of labor hours in the field! There were a few issues in getting started in the right direction -- but a very efficient operation when properly organized...

 

[Rewire]

The last prevailing wage job we did I had the shop boy prefab stuff to send out it saved us a few dollars over doing it on site

 

[Red Wiggler]

Pre-fab

Pre-fab

I work in the Pre-planning dept. for an Electrical contractor that wants me to have a minimum of 20% of each job to be done in our enviromentally controlled "pre-fab" dept. This includes...
pre-fabricated 90 degree rigid bends grouped together (depending upon various configurations to match gear footprint)for underground work.

Pre-fabbed concrete boxes for block/brick work, with conduit nipples (boxes duct-taped)

Pre-fabbed fixture whips, and can lights made with brackets that screw directly to the hat-channels or studs.

All of our wire is cut from master reels. This includes feeder wire on "comp" reels, multiple runs of MC cable on reels (labled and numbered), control wiring grouped, numbered and bundled.

We build all of our control cabinets (if we get the sub-contract).

Pre-fab duct-bank sections (based on pipe size and configuration)

I know there is more I just can't remember it all.

 

[walkerj]

I usually prefab stuff early during the job when things are slow.
Things like light whips, 90's, Ground jumpers and prings on boxes.
View attachment 2895

 

[petersonra]

Guys that know how to cut costs seem to use this as one of their techniques.

I was on a job site a while back where the foreman seemed to spend most of his time sending faxes back to the shop to have bends and odd ball pieces made up.

Some of the chunks that came in were pretty impressive. One came in on a Unistrut frame ready to mount to a wall. All they had to do was bolt it to the wall. It even had wiring in it that went to a jbox near the top of the assembly.

I have also seen a fair number of contractors using the prefabricated wire bundles that have individually numbered conductors. A whole lot faster to figure out what wire goes where.

One of the coolest things I ever saw was a contractor that assembled a conduit rack on the floor with all the conduit and other chunks and then lifted the thing into place with a couple fork lifts. They did what looked like about 20 foot sections at a time.

 

[charlietuna]

We piped the high rise concrete slabs with EMT -- we came up with a method to cut all the stub-ups off at 5 inches--a portaband saw mounted on a portable wheeled platform. Taped couplings were immeadiately installed for safety and the short stup-up was less apt to get damaged by it's own heigth. We then used scrap EMT to make 11 inch EMT nipples after they went thru an custom offset machine. This offset allowed you to roll the outlet box to be flush with the stud during the "box-out" phase.. This kept us busy between slabs. When we got ready to box-out a floor this method, coupled with using prefabricated boxes from the shop allowed two men to box out a floor in a day. We also prefabricated panels, panel stub-ups. We made templets of the panel knockout pattern and the home runs came into each panel always at the same location. Again offset EMT was prefabricated for the proper panel heigth. Another labor saver was to prefabricate EMT with a standard 90 prior to sending it up to the slab. The installation of EMT on the deck was mainly accomplished without a bender. I came across a very old-one shot- EMT bender. This bending was done by the slab crew between slabs which again would be "DEAD TIME"! New comers to the job always had their doubts about this system, but were sold on the end result because it made their job so easy. The only waste on EMT were those nipples cut off by the "lawnmower"--re: port-a-band rig, and they were carried off the slab in a five gallon bucket(safety)!

 

[480sparky]

I usually prefab stuff early during the job when things are slow.
Things like light whips, 90's, Ground jumpers and prings on boxes.
View attachment 2895

Prings? Teach me, Master Po.



I used to work for an outfits that was a prefab nuthouse. Their motto was "Anything done on the jobsite more than once can be done cheaper in Prefab."

Schools were a great use of prefab. Every classroom has at least 2 or 3 data drops, so Prefab would put together a 232 box, connector, mudring, EMT, straps and a 90 at the top. Walk in with a cordless and some screws, and bam.... done. Beat feet to the next room.

If you planned the job right, you could rough-pipe a classroom in about 2-3 hours. Not just power & lights, but data, intercom, master clock, fire alarm, the whole shebang.

WalMart spec'ed steel rigid 90s coated with roofing tar for the bends at light poles, but for some reason, Prefab refused to do those.:roll:



Now I've got this Carley Simon song in my head.........

 

[76nemo]

Pre-fab can save lots of time and $, but it takes good coordination. We used to build ahead for certain things that we got prints for well ahead of time. You get everyone on the same page, and pre-fab can REALLY benefit!!! If you get everything properly labeled, than things can roll real quick:wink: That was the key, we all had the same prints, everything numbered and labeled properly and you could smoke out some work real fast!

 

[Fulthrotl]

I?m curious who utilizes prefabrication to increase profits? I like the idea of Quality prefab if done efficiently.

Feedback is welcome

JJ

prefabrication and prestaging are huge profit generators.

ideally, when someone walks into an area of a project, having everything they
need right there, and ready to go means the job runs under a high PSI...
putting stuff in.... which is what we get paid for.

in the late 80's, i worked for a contractor that was 4th largest in the nation,
at that time, and they did it with high rise TI in LA and Orange counties, in
calif.

prefab, prefab, prefab...... bought a nice yacht docked at cabo san lucas
for the owner of the concern.

in one day, on a deck, running smurf tube, with a guy ahead of me laying
out walls, i got 12,000 feet of smurf ran.... and it was cause i didn't have to
move farther than 4' from the work all day, 'cept to use the porta potti.

everything was *right there*, and by that, i mean i didn't even have to walk
across the deck to get something.

of course, having the pour at 6 am the following morning was a motivational
aspect that cannot be ignored either....

 

[walkerj]

Prings? Teach me, Master Po.

I meant to type p-rings.
Plaster rings.

 

[petersonra]

Where I used to work, we made a ton of money by being able to install things for less than our competitors. Most anything you do that reduces field labor is cost effective.

Most of the techniques for reducing field labor are well known these days.

 

[Rewire]

we did wire runs ,we would get a measurement and size and # of cunductors spool them all on a single reel tie the ends to jack chain and send them to the job all that needed done on site was pull in a tape set up the reel attach the jack chain and pull

 

[220/221]

When I first started in the mid 70's doing tract houses, we would prefab a ceiling light box with four 142's and a 14/3 coming off for individual rooms. It seriously cut down labor cost on both rough and trim.

Nail up the box, drop the legs to receps/switch, and put in a jumper somewhere.

I am a big fan of prefab but the make up in the prefabbed commercial stuff I have seen is really ugly.

 

[shockin]

I'm going to disagree slightly on the fact that pre-fab WILL ALWAYS reduce costs. It will only save you money if you have a labor rate that averages $7.00 an hour IMO. If you have $30.00 an hour journeymen doing the work it won't work.

Another thing is there are some tasks that seem to make sence but they don't work. Here's an example. A 2X4 troffer that needs lamps and a whip. A person in the prefeb shop needs to open the troffer box and perfrom the work. Reclose the box, repaletize the boxes in order to ship it to the site where they re-open it. You have spent way to much time just dealing with packaging and shipping. This task could be done much more efficently at the site. Have your $7.00 an hour guy there open the box lampit, whip it, and be done.

Not the best example because if your not ordering your troffers pre-lamped, and pre-whipped with reloc in a job pack you've already missed the boat. But you get my point.

 

[charlietuna]

Shockin,
Thats only one "pre-fab" task that will not work to save money in the field and common sense tells you it is too labor intensive to re-package a light fixture. But if(?) you had mechanics in the field building whips compared to a guy with a 500 foot roll of flex mounted above a work bench and cutting it with a chop saw--passing it on to a second guy with three rolls of wire to install into each whip. The task must be labor saving--not duplicate work--that wastes labor!!! If you could find $7.00 an hour labor that knew what the $30.00 an hour mechanic wanted in the field--then a $7.00 an hour man might(?) work out as the pre-fab guy! Now the $7.00 an hour pre-fab man has the whips finished and his next task is to bend four 2 inch EMT's with a six inch offset on each, and the next task is to build ten 4 11/16 boxes with three one inch steel EMT connectors and two 1/2 inch steel connectors out the last side of the box. What do you think you would end up with???? We had electricians pre-fabbing for electricians and the labor saved was because things were mass produced and inbetween their labor was used for pipe bending--maybe some control assembly....

 

[daleuger]

Shockin,
Thats only one "pre-fab" task that will not work to save money in the field and common sense tells you it is too labor intensive to re-package a light fixture. But if(?) you had mechanics in the field building whips compared to a guy with a 500 foot roll of flex mounted above a work bench and cutting it with a chop saw--passing it on to a second guy with three rolls of wire to install into each whip. The task must be labor saving--not duplicate work--that wastes labor!!! If you could find $7.00 an hour labor that knew what the $30.00 an hour mechanic wanted in the field--then a $7.00 an hour man might(?) work out as the pre-fab guy! Now the $7.00 an hour pre-fab man has the whips finished and his next task is to bend four 2 inch EMT's with a six inch offset on each, and the next task is to build ten 4 11/16 boxes with three one inch steel EMT connectors and two 1/2 inch steel connectors out the last side of the box. What do you think you would end up with???? We had electricians pre-fabbing for electricians and the labor saved was because things were mass produced and inbetween their labor was used for pipe bending--maybe some control assembly....

When I was still pushing the broom and not too good on the bender (or a lot of other tools yet) one of the common tasks for us green guys was to make up all the 2x4's with the six foot whips already hanging out. The MC is already stripped and a connector put on. All the man putting in the light has to to is drop the light in the grid and put the end of the whip in the j-box. This was done on the job but IMO it does keep journeymen on more important tasks.

 

[petersonra]

I'm going to disagree slightly on the fact that pre-fab WILL ALWAYS reduce costs. It will only save you money if you have a labor rate that averages $7.00 an hour IMO. If you have $30.00 an hour journeymen doing the work it won't work.

I think you are misisng the point. it not about doing prefab work with guys you are paying less. It is about doing prefab work in ways that are more efficient than doing them on a job site as you are doing the work.

You probably do a lot of prefab work yourself and don't even realize it.

Ever put an EMT adapter in a 2X4 box before you nailed the box in place?

Ever install whips to a light fixture before you hang it?

 

[charlietuna]

Why would anyone buy a layin fixture without it being "lamped and whipped" in 2009 ?