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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Mike Sokol on July 29, 2015, 08:23:09 pm

Title: Tapped Out
Post by: Mike Sokol on July 29, 2015, 08:23:09 pm
I don't know where to start with this one.... :o
Title: Re: Tapped Out
Post by: Mark Cadwallader on July 29, 2015, 08:54:38 pm
But it must be OK; there is a UL tag on it....
Title: Re: Tapped Out
Post by: Lyle Williams on July 29, 2015, 09:19:39 pm
Some guys here were talking about providing power (years ago) in a remote area, with a little third world village nearby.  The load on the generators seemed too high, and when they shut things down to investigate the village went dark.

They found nails through their feeders and burried telegraph wire heading towards the village.
Title: Re: Tapped Out
Post by: Stephen Swaffer on July 29, 2015, 10:11:41 pm
The first problem is the wire is wrapped the wrong way around the screw. 
Title: Re: Tapped Out
Post by: g'bye, Dick Rees on July 29, 2015, 10:13:49 pm
The first problem is the wire is wrapped the wrong way around the screw.

I wondered about that...but then I realized it's LH threads.
Title: Re: Tapped Out
Post by: Jeff Bankston on July 29, 2015, 10:43:08 pm
A drywall screw ! Thats just tacky ! He should have used a wafer head A point TEK screw instead. Much classier.
Title: Re: Tapped Out
Post by: Scott Wagner on July 30, 2015, 01:49:50 pm
I saw this on the BookFace the other day. My reply was (and remains), "someone would be getting an invoice for new feeders."
Title: Re: Tapped Out
Post by: Mike Sokol on July 30, 2015, 01:52:09 pm
A drywall screw ! That's just tacky ! He should have used a wafer head A point TEK screw instead. Much classier.
I wonder if they killed the power before drilling the feeder with a drywall screw?  ::) 
Title: Re: Tapped Out
Post by: Jonathan Johnson on July 30, 2015, 02:48:48 pm
The wire nut is a size too small?
Title: Re: Tapped Out
Post by: Mac Kerr on July 30, 2015, 03:59:12 pm
The wire nut is a size too small?

How can you see the nut, it must be on the other side of the wire.

Mac
Title: Re: Tapped Out
Post by: TJ (Tom) Cornish on July 30, 2015, 04:05:50 pm
How can you see the nut, it must be on the other side of the wire.

Mac
Pretty sure he means the blue one.
Title: Re: Tapped Out
Post by: Steve Alves on July 30, 2015, 11:10:51 pm
I don't get it, if you are going to do something that stupid, surely there was a lug somewhere in the box that they could have jammed that wire into. It would have been just as bad but I would have rather seen a double lug then that.
Title: Re: Tapped Out
Post by: Jeff Bankston on July 31, 2015, 02:49:44 am
I don't get it, if you are going to do something that stupid, surely there was a lug somewhere in the box that they could have jammed that wire into. It would have been just as bed but I would have rather seen a double lug then that.
yep just as bad !

                         http://www.youtube.com/watch?v=rSjK2Oqrgic
Title: Re: Tapped Out
Post by: Mike Sokol on July 31, 2015, 06:43:51 am
yep just as bad !
As a teachable example for those who don't know, I'm sure you all realize that that if the small wire shorted out somewhere, there's no circuit breaker to trip. And it could easily be asked to pass hundreds of amperes of current, causing it to vaporize and making something called an arc-flash blast. That's WAY dangerous since the resultant fireball is hotter than the surface of the sun moving at faster than the speed of sound. It's an electrician's worst nightmare. https://www.youtube.com/watch?v=dPJtknGmsys
Title: Re: Tapped Out
Post by: David Allred on July 31, 2015, 08:42:18 am
The first problem is the wire is wrapped the wrong way around the screw.
Only on PSW!   Ha.
Title: Re: Tapped Out
Post by: Mike Sokol on July 31, 2015, 10:00:40 am
Only on PSW!   Ha.
The devil is in the details.
Title: Re: Tapped Out
Post by: Stephen Kirby on July 31, 2015, 12:44:00 pm
The wire nut is a size too small?
Or the strip is too long.  Love the backwrap on the screw too.
Title: Re: Tapped Out
Post by: Mike Sokol on July 31, 2015, 02:50:30 pm
Or the strip is too long.  Love the backwrap on the screw too.
Ummmm..... I think we're way beyond discussing best practices for wire nuts. But since we're there, I like to do mine twisted and taped.
Title: Re: Tapped Out
Post by: Stephen Kirby on July 31, 2015, 04:50:03 pm
I guess they don't make these in 000 size.   ::)

(https://img3.fastenal.com/productimages/60097.jpg)

On a slightly more serious note;  Mike, what is your opinion on the "waterproof" wire nuts.  I've used them on my sailboat but I see them in the hardware stores as if they were an improvement for home wiring.

I've long thought that whoever wrote the NEC had stock or relatives in the wire nut industry.  As a manufacturing engineer with background in weapons spec electronics, that's probably the last way I would choose to hook wires together.  Especially in things like putting two duplex outlets in a box as opposed to using both terminals and the tie bar.
Title: Re: Tapped Out
Post by: Mike Sokol on July 31, 2015, 05:45:14 pm
On a slightly more serious note;  Mike, what is your opinion on the "waterproof" wire nuts.  I've used them on my sailboat but I see them in the hardware stores as if they were an improvement for home wiring.
Others on this forum are likely more involved with wire nuts, but I've seen these waterproof nuts in a few stores and always passed over them. For serious waterproofing we always used self-sealing electrical tape which makes its own gooey sealant. Of course it's nearly impossible to get the mess apart a year later, but I'm pretty sure it's not going to leak. Of course, anything like waterproof wire nuts or self-sealing tape is not a substitute for a weatherproof enclosure, but it's certainly a good backup if the enclosure seal fails for any reason.
Title: Re: Tapped Out
Post by: Jonathan Johnson on July 31, 2015, 07:34:01 pm
On a slightly more serious note;  Mike, what is your opinion on the "waterproof" wire nuts.  I've used them on my sailboat but I see them in the hardware stores as if they were an improvement for home wiring.

You cannot seal water out. But you sure can seal it in. Waterproof all you want to keep the water from getting in, but for goodness' sake, leave a way for water to get OUT.

That's why in outdoor boxes I always orient the wire nuts so the opening is DOWN.
Title: Re: Tapped Out
Post by: Tom Bourke on July 31, 2015, 08:04:50 pm
Especially in things like putting two duplex outlets in a box as opposed to using both terminals and the tie bar.
Is the tie bar not permitted for pass threw?  What about the screw down back wire outlets where the two wires fore each outlet share a common plate?(http://inspectapedia.com/electric/Receptacles_0580_DJFs.jpg)
Title: Re: Tapped Out
Post by: Stephen Kirby on August 01, 2015, 01:07:55 am
My understanding is that you're supposed to put two short pigtails into a wire nut and run each to it's own duplex.  Maybe this has been updated.
Title: Re: Tapped Out
Post by: Steve M Smith on August 01, 2015, 04:03:46 am
I still can't believe that your wire nuts are considered to be an acceptable method of connection!


Steve.
Title: Re: Tapped Out
Post by: Jeff Bankston on August 01, 2015, 04:28:58 am
I still can't believe that your wire nuts are considered to be an acceptable method of connection!


Steve.
I'v ben a commercial electrician for over 20 years and wire nuts are a much betterconnection than screw connections. i use wire nuts on my roadrace mustang because they dont vibrate loose. i have come across many loose screws on commercial jobs in earthquake california. wire nuts twist the wires and the tapered spring cuts tiny threads into the wires. it can be a mutha to get wire nuts off. i cant believe you guys dont use wire nuts.
Title: Re: Tapped Out
Post by: TJ (Tom) Cornish on August 01, 2015, 07:05:25 am
My understanding is that you're supposed to put two short pigtails into a wire nut and run each to it's own duplex.  Maybe this has been updated.
One wire per screw is fine, and if the device has a clamping plate, each screw has facilities for two wires. Passing the hot and neutral on to the next device using these means is standard procedure.  Ground wires require pigtails and a wire nut, however, as there is only one ground screw per device.
Title: Re: Tapped Out
Post by: Steve M Smith on August 01, 2015, 08:23:25 am
i have come across many loose screws on commercial jobs in earthquake california. wire nuts twist the wires and the tapered spring cuts tiny threads into the wires. it can be a mutha to get wire nuts off. i cant believe you guys dont use wire nuts.

Does your wiring have multi strand conductors?  Ours are solid copper which I don't think would work with wire nuts.

(http://wiki.diyfaq.org.uk/images/d/d0/FlatT%26E.jpg)

Push fit connectors are becoming popular here.  They used to be used internally in light fittings and some other equipment.

https://www.connexbox.com/index.php?source=adwords&gclid=CODDlOjxh8cCFaPnwgodxWMGDw


Steve.
Title: Re: Tapped Out
Post by: TJ (Tom) Cornish on August 01, 2015, 08:30:37 am
Does your wiring have multi strand conductors?  Ours are solid copper which I don't think would work with wire nuts.

(http://wiki.diyfaq.org.uk/images/d/d0/FlatT%26E.jpg)


Steve.
NM/Romex used for branch circuits up to 30A in residential construction is solid, just like your picture.  Wire larger than #10 is nearly always stranded.  THHN wire used commercially is usually stranded.  Wire nuts work fine either way, but you need to use the right size wire nut.
Title: Re: Tapped Out
Post by: Steve M Smith on August 01, 2015, 08:36:11 am
I'm sure they're fine. They just 'don't look right' if you're not used to seeing or using them.

The most ridiculous connection I have seen was the power to the shed in my previous house which was 'installed' by the previous owner.  A few weeks after I moved in, the power in the shed started flickering then eventually stopped working completely.

I was intending to move the shed and when I did, I dug up the buried cable which was solid conductor 2.5mm intended for internal use.  Half way along its length was a join.  The wires had just been twisted together, taped up and buried in the earth.  No wonder it failed!


Steve.
Title: Re: Tapped Out
Post by: Tom Bourke on August 01, 2015, 09:45:33 am
Push fit connectors are becoming popular here.  They used to be used internally in light fittings and some other equipment.

https://www.connexbox.com/index.php?source=adwords&gclid=CODDlOjxh8cCFaPnwgodxWMGDw


Steve.
We have "back stab" outlets kind of like that.  They suck.  They only use a little spring to bite into the wire.  Run any current on them and they heat up and fail, some times very badly.  I will only use side wire or back wire where the screw clamps down.  Wire nuts are spring loaded as well but they use wire to wire contact and the spring is just to keep that connection from loosening.
Title: Re: Tapped Out
Post by: frank kayser on August 01, 2015, 10:07:02 am
We have "back stab" outlets kind of like that.  They suck.  They only use a little spring to bite into the wire.  Run any current on them and they heat up and fail, some times very badly.  I will only use side wire or back wire where the screw clamps down.  Wire nuts are spring loaded as well but they use wire to wire contact and the spring is just to keep that connection from loosening.
Some of the better back-stab outlets actuallly use the side screws connected to a clamp inside - one clamp per pair - and are actually quite secure.  I agree about the spring load back-stab - don't trust 'em, and they also score/nick the wire which I've seen becone a failure point.
frank
Title: Re: Tapped Out
Post by: Steve M Smith on August 01, 2015, 11:11:33 am
We have "back stab" outlets kind of like that.  They suck.  They only use a little spring to bite into the wire.

I don't think I would use them.  I don't use push fit plumbing fittings either.


Steve.
Title: Re: Tapped Out
Post by: frank kayser on August 01, 2015, 12:48:23 pm
I don't think I would use them.  I don't use push fit plumbing fittings either.


Steve.
My experience is VERY limited - my plumber showed me the Shark Bite push-on fittings. They do work easily, and seem well designed. Great for places where one just can't get the propane torch. (torch in English is flashlight - so Steve, what do they call a propane soldering torch  on that side of the pond...)
Title: Re: Tapped Out
Post by: Jeff Carter on August 01, 2015, 02:04:11 pm
My experience is VERY limited - my plumber showed me the Shark Bite push-on fittings. They do work easily, and seem well designed. Great for places where one just can't get the propane torch. (torch in English is flashlight - so Steve, what do they call a propane soldering torch  on that side of the pond...)

The other nice thing about Shark Bites is that if you have to, you can push a valve on while the water is pouring out full bore. I changed the main shutoff valve in my basement a couple of years ago that way, though my brother (who's a plumber) cringed a little when I told him the story afterward.
Title: Re: Tapped Out
Post by: Steve M Smith on August 01, 2015, 02:29:56 pm
My experience is VERY limited - my plumber showed me the Shark Bite push-on fittings. They do work easily, and seem well designed. Great for places where one just can't get the propane torch. (torch in English is flashlight - so Steve, what do they call a propane soldering torch  on that side of the pond...)

Gas torch.

In my last house, I had one push fit connector... in the roof... and it let go of the pipe when I wasn't there.

(I think you meant flashlight in English is torch).


Steve.
Title: Re: Tapped Out
Post by: Daniel Levi on August 01, 2015, 02:40:14 pm
A propane torch in England is generally called a blowtorch.

Title: Re: Tapped Out
Post by: Jeff Bankston on August 01, 2015, 03:46:30 pm
Does your wiring have multi strand conductors?  Ours are solid copper which I don't think would work with wire nuts.

(http://wiki.diyfaq.org.uk/images/d/d0/FlatT%26E.jpg)

Push fit connectors are becoming popular here.  They used to be used internally in light fittings and some other equipment.

https://www.connexbox.com/index.php?source=adwords&gclid=CODDlOjxh8cCFaPnwgodxWMGDw


Steve.
stranded wire is illegal to connect to a 15a U ground outet unless it has spade connectors crimped on it and we dont use stranded except for motors. we use #12 solid wire for recepticals on commercial jobs. #12 is the minimum size allowed on commercial jobs. i dont do house wiring but all of it is #14 or #12 romex solid wire. when #10 stranded and larger is used crimp on connectors are used if the outlet doesnt have a hole with a clamp that clamps down on the wire. wire nuts work exelent with solid and stranded wire. the best thing about wire nuts is they squeeze the wire very tight and it will not loosen. wire nuts are as good as a solder joint. hand held torches became obsolete for soldering building wire in the 70's.
Title: Re: Tapped Out
Post by: Rob Spence on August 01, 2015, 04:20:10 pm
One wire per screw is fine, and if the device has a clamping plate, each screw has facilities for two wires. Passing the hot and neutral on to the next device using these means is standard procedure.  Ground wires require pigtails and a wire nut, however, as there is only one ground screw per device.

Current code (as 2008 residential ) doesn't permit wire nuts on grounds. They have to be twisted and crimped.


Sent from my iPad using Tapatalk HD
Title: Re: Tapped Out
Post by: Stephen Swaffer on August 01, 2015, 10:59:09 pm
Iowa inspectors do require a "pressure connector" on grounds-but wire nuts are acceptable and UL listed for the purpose.

At a continuing ed class as state inspector, when asked about using crimp on connectors for stranded wire on receptacles argued that the receptacles are "listed" for use with stranded or solid wire-not with spade connectors.

Just depends on the AHJ as to what you can do. Lacking the presence of an AHJ, everyone has their preference. I almost always pull stranded wire in conduit, but a fair amount of commercial wiring in this area uses MC cable.  I did some work for a Bible camp close to me that is owned by a church from the Chicago area.  When we built some new cabins, code allowed us to use romex to wire them-but the electricians (licensed and experienced) from their church did not know the proper methods for running romex, since everything in their area (including residential) is required to use emt/conduit.

Like most materials, wire nuts work great when properly applied.
Title: Re: Tapped Out
Post by: Jeff Bankston on August 02, 2015, 01:14:16 am
Iowa inspectors do require a "pressure connector" on grounds-but wire nuts are acceptable and UL listed for the purpose.

At a continuing ed class as state inspector, when asked about using crimp on connectors for stranded wire on receptacles argued that the receptacles are "listed" for use with stranded or solid wire-not with spade connectors.


In Los Angeles the dept of building and safety requires spades to be used with stranded on recepticals that I call Type One. There is no way to keep all the strands under the screw head and properly tighten it.