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Re: Vacuums and Wire Pulls [Re: renosteinke] #215646 06/19/15 12:08 PM
Joined: Dec 2000
Posts: 4,283
electure Offline
Member
While we're speaking of ferrets Reno, you're that not far off base.

One of my ex-employers bought enough from a wholesaler that he and 9 other contractors were given free 10 day trips to London.

When they were visiting Buckingham Palace, they learned that all the underground conduits (originally installed in the 1910s and '20s) used ferrets to pull the strings through them.

Work Gear for Electricians and the Trades
Re: Vacuums and Wire Pulls [Re: renosteinke] #215653 06/21/15 07:19 PM
Joined: Nov 2002
Posts: 789
W
wa2ise Offline
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Saw in the paper a few days ago, that the Parliament building in London is in serious need of renovation. Bad roof, ancient wiring, and similar issues. Wiring probably done back when they used ferrets. smile

Re: Vacuums and Wire Pulls [Re: renosteinke] #215654 06/21/15 11:28 PM
Joined: Apr 2002
Posts: 7,177
HotLine1 Offline
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OK I will say that using CO2, or compressed air, may be easier to setup on site. Even that a smaller shop vac would be convenient, and should be 'easier to haul'.

When we were on a site with no 120/240 we had a genset. There was one on the bucket truck, and another could be from the shop. PVC jobs had the hotbox, and/or the blankets, Pipe most times had a power bender, and the 'big' pulls had the tugger. Sometimes it may have given the appearance of a Greenlee site demo.

No, the equipment wasn't used daily, but it was used when it was needed. A sort of bonus was the 'rental' from others who had a need. Ranged from 'favors' to $$$.



John
Re: Vacuums and Wire Pulls [Re: wa2ise] #215655 06/22/15 08:18 AM
Joined: Dec 2001
Posts: 2,483
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Texas_Ranger Offline
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Originally Posted by wa2ise
Saw in the paper a few days ago, that the Parliament building in London is in serious need of renovation. Bad roof, ancient wiring, and similar issues. Wiring probably done back when they used ferrets. smile


Same in Vienna, but probably no ferrets. I've seen pictures of exposed K&T in utility areas! Apparently driving huge arrays of incandescent bulbs used both to light the plenary and to melt any snow and ice from the glass roof.

Re: Vacuums and Wire Pulls [Re: renosteinke] #215667 06/27/15 12:14 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline OP
Cat Servant
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Well, if this current job is any indication, here's what needs to be done to ensure a painless pull:

First, for any long or complex run, consider 'going up' a conduit size.

Next, pay particular care to your transitions. Many folks 'stub up' in steel, and do the bulk of the underground run in PVC. The transition can be a real 'catcher' of mice and fish tapes .... why can't our transition fittings have a taper to them, like plumbing 'bells' do?

Buried PVC connections need primer as well as cement, and a wrap of duct tape isn't a bad idea. EMT connections definitely need to be wrapped, or otherwise sealed, on long runs. You want to keep water out, if you can. (On this job, we even had an overhead run fill with water!)

Tape itself doesn't seem to be enough to protect your stub-ups. Somehow, the tape gets torn and crud dropped in. Deliberate malice or just Murphy's law? I don't know- but next time I might try attaching a soft foam plug to the pull string, just inside the pipe, at either end.

Protect your threads on stub-ups with couplings and proper pipe plugs.

This job has also shown a real need to brace the **** out of the stub-ups, to preserve their alignment during the pour, etc. This means I'll be burying some strut, running the conduit within rigid sleeves, or taking other additional measures.

Your vacuum need not be large. You don't need a big tank or a high-horsepower motor. Ironically, on this job we had a little 1-gallon Shop-Vac out-pull a 5-hp, 10-gal heavy duty vac. It's not so much the pressure you need, as the air volume .... remember, NO vacuum can create more than about a 14-psi suction.

Which, of course, brings up the condition of the vacuum. There's an argument to be made for using a dedicated vacuum ... and, in any event, to protect the vacuum with the best filter you can get. Vacuum performance is dramatically affected by even a microscopic amount of wear on the impeller ... and drywall dust is instant death to blower performance.

I spent about $15 on a "micro cleaning" kit that provided me with various attachments. With a modest amount of tape, I can now reach into conduit, even when it's off to the side of a mud ring, and get a good seal. I'm essentially duplicating the big Greenlee fitting- but in a smaller, more maneuverable size. Plus, the mouse won't get sucked into the vacuum; instead, it sticks onto the end of the nozzle.

Ironically, the $21 bucket-top vacuum seems to best fill the bill. Heck, you can even find 3- and 4-gallon buckets to mount the top onto, making it much more ladder-friendly. The 1-1/4" hose seems to move plenty of air. Best of all, you can store the hose, etc., in the bucket between uses.

(Full disclosure here: I'm now working with a trade tool manufacturer to develop a vacuum targeted to our needs- for less than a car payment, let alone the cost of the whole car!)

This job has been a wire-pulling nightmare. I have two pipes, full of wire, that had to be abandoned. For both, we got the wire about 90% through before it stuck, and could not be pulled out. Think: 5000 ft. of #10 wire lost. Sort of puts the cost of PVC primer and duct tape in perspective.

Re: Vacuums and Wire Pulls [Re: renosteinke] #215668 06/27/15 01:02 PM
Joined: Apr 2002
Posts: 7,177
HotLine1 Offline
Member
Over the years, my crews and myself must have always had a 'lucky charm' in our pockets.

"Think: 5000 ft. of #10 wire lost"

I have to feel your pain Reno. Yes, I was (and still am) a preacher of using conduit sizes larger than the code min.

BTW, never primed or taped a PVC run.



John
Re: Vacuums and Wire Pulls [Re: renosteinke] #215669 06/27/15 01:27 PM
Joined: Mar 2004
Posts: 947
T
twh Offline
Member
With a vacuum all you get is what the motor can deliver. With a compressor, you can store the energy in a tank and your limitation is how fast you can get the air out of the tank.

A piece of soft plastic tied into a balloon shape seems to work better than a factory mouse.

You should get a patent on the tapered fittings.

I've been using strut on stub ups through concrete. Is there another way? If the stub is ENT (Coreline) I sleeve it with vacuum line duct. I also run spares for anything that can't be re-done overhead later. It's pretty sad how much damage the cement guys can do.

Prime PVC fittings?

Re: Vacuums and Wire Pulls [Re: renosteinke] #215670 06/27/15 01:41 PM
Joined: Jul 2004
Posts: 9,482
G
gfretwell Offline
Member
I don't think it is a bad idea to prime RNC connections. It is not as much the priming function as simply cleaning it but the cement seems to work better. You really do not want a joint to pull open when it is back filled.


Greg Fretwell
Re: Vacuums and Wire Pulls [Re: renosteinke] #215671 06/27/15 05:34 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline OP
Cat Servant
Member
To be clear, there is no "mea culpa" here. The underground pipe was run months before I ever saw the job. I can't speak for the original quality of the job, and it's anyone's guess what happened in the meantime.

In perspective, I'd rather be a bit anal and overly cautious now, rather than fuss & cuss later!

I noticed in today's "Electrical Contractor" magazine that Bridgeport is plugging a whole line of transition fittings. Perhaps these are less likely to cause problems than a field-expedient improvised transition assembly.

Sure would have been nice had NEMA specified the same ID for ALL conduit types! That small lip can be just enough for the wire to catch.

As for compressors ... I have no objection to the method. It's more a question of what you have available. On this current job, we have not had a compressor available- but we have used vacuums in tandem (one pulling, one pushing).

Best results were with a 'real' (foam) mouse and jet line. Yes, we know the plastic bag trick, and it was used several times, but the mouse worked better. The only problem was knowing when the mouse had arrived at the other end; often we had no idea it had entered the vacuum.

Jet line was followed by pull string. Then a mouse was pulled through several times - both to clear debris as well as to spread lube. Then a real rope was pulled in. Wire 'heads' were stripped of insulation, staggered very well, and the wire itself braided back onto itself. A very long, smooth, skinny head that did not depend on tape to hold it together.

Re: Vacuums and Wire Pulls [Re: renosteinke] #216143 10/16/15 04:28 PM
Joined: Feb 2004
Posts: 1,432
Lostazhell Offline
Member
Having just come out of my first solar field job (Which I came into about the 2/3rds point) I must say that the common sense (and code practices) that a general electrician uses when it comes to conduit installation did NOT reach the design phase of this job. I saw the most bizarre things over there....

2" PVC 40 stubs coming from a pad, had 1" "duct" shoved inside maybe a foot and then duct seal was stuffed around the 1". This duct was for fiber with was about 1/2" diameter and runs ranging from 400' to one just above 3500'! Through this we were expected to suck a string through. Unused conduits were stuffed with duct seal. (There was literally 2 pallets of duct seal on this job and nothing was "fire rated". Duct seal was easier to find than duct tape! crazy )

We managed to get string in some of the runs with a large shop vac and generator. For a couple runs we "borrowed" a hydro dig machine that was onsite and used the vacuum hose on it, still having to use a slinkied fish tape to catch the balloon in the 2".

Did I mention there were up to 7 - 90 bends in some of these runs??? blink

We ended up using a pulley attached to a Landall forklift and an atv to do the pulling. Some runs made it, and on some we snapped 2500# muletape. A kellems and a 5 gallon bucket of aquagel was used on every run.... Eventually I found out that this ducting was run through some bizarre routings around the solar tables "because thats what they drew on the print!". (One run was about 450'-500' if you walked from end to end. The pull used 1486' of fiber in the ground somehow???)

The job was supposed to be done last August and the group who owns the field finally kicked the EC off the job and hired another one. I'm deciding if I want to roll in with the new EC and take on the headache I know this place will be with the over strained fiber pulls, grounding issues and who knows what else. Lots of OT (7 X 12's) so it'll be nice for the bank account but will I live to spend it? laugh

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