Another electrical question for shop wiring

[Alan Tolchinsky]

Hi All, Well great news! I just passed my rough in spection of my shop wiring. I've done it all in EMT conduit with a subpanel and using all 20 amp circuits. The inspector noted one thing on the rough in though. He told me it was not up to code to have stranded wire wrapped around a screw. He was talking about my box ground wires but it applies to all connections. He said you needed to have crimp on connectors. I don't like doing those connections and feel they are not real secure(at least the way I do them).

Any other ideas on terminating stranded no. 12 wire on a screw? Or should I just learn how to do crimp ons better. Thanks!

[Art Mann]

Just buy a quality crimp tool instead of wire pliers and get yourself a box of spade lugs of the appropriate size. Correcly crimped wires are utterly reliable. Automobiles have hundreds of crimp connections of just this sort. I know because I used to specify such things for a big three manufacturer.

[Jim Myers]

They make screw type blade connectors that go onto ends of cables but you probably just need to crimp then solder the ends and they will rarely fail after that.

I have used many different kinds but if I wanted to make sure it was a good connection I alyaws solder the crimps. (old habbit from NAVY days)

[Greg Cole]

Alan,
If you get the proper size terminals for the wire gauge & a set of the crimpers for the terminals they are plenty secure.
I deal with Euro manufactured machinery at the day job, and all their wiring has crimp on ferrules (pin connectors or some type of crimp on connector). We use these style wire connection for everything from 4-20MA, 24V control power loops to 480V at 600A (250 HP motors are not uncommon).
Crimp style connections are secure when done properly IMHO as if they are suitable for industrial applications in a VERY difficult enviroment (refridgerated & humid), they are fine for residential applications.
For all the faith put in wire nuts in residential wiring... a crimp connection shouldn't be a worry.

Regardless of my opinion, do as the inspectors asks and move on to getting the shop done!

Best of luck.

Greg

[Tyler Howell]

[quote=Art Mann;623625]Just buy a quality crimp tool instead of wire pliers and get yourself a box of spade lugs of the appropriate size. quote]
What he said!!

[Rod Sheridan]

Another method is to purchase receptacles that are side wired and have terminal plates.

These plates allow either a solid or stranded conductor to be used, since the conductor is sandwiched between the two plates.

Any electrical supplier will have these devices..........Rod.

[Rob Russell]

Another method is to purchase receptacles that are side wired and have terminal plates.

These plates allow either a solid or stranded conductor to be used, since the conductor is sandwiched between the two plates.

Any electrical supplier will have these devices..........Rod.

Part of running raceway (in this case he used EMT) is grounding all of the boxes. You can use the EMT itself or you can take the extra safe route and run the grounding conductor to the green grounding screws in the boxes ... it's my guess that's what Alan was talking about.

[Alan Tolchinsky]

Thanks for all the info. guys. I have a crimping tool but it's a wire stripper also and not real effective for crimping. I'll have to get a quality one. I like the idea of soldering; that I've done a lot. I'm going to check the Borg and see what they have. I am using as many side terminal outlets as possible. Boy I love these: You just insert the wire into the hole and tighten the screw and they work great with stranded or solid. But some of my 220 outlets only have screw connections and I want to be sure these are on securely. And I have to make up crimped connections for all the box grounds. Thanks for all the ideas!

[Alan Tolchinsky]

Part of running raceway (in this case he used EMT) is grounding all of the boxes. You can use the EMT itself or you can take the extra safe route and run the grounding conductor to the green grounding screws in the boxes ... it's my guess that's what Alan was talking about.


Yes Rob, that is one of my concerns. I am grounding all the boxes with a screw in each box. But I also have some 220 outlets with screw connections and they just don't work with stranded wire. Thanks.

[Jim O'Dell]

I think I saw a Kline crimper at Lowes the other day. May have been a Kline knock off. I've had a knock off for about 12 years that is great. I got it from one of the mobile terminal suppliers that supplied us at a shop I used to work at. Seems like the one I saw at Lowes was in the 20 to 25 dollar range. One red handle, one black handle. Jim.

[Alan Tolchinsky]

Can you do good crimps with one of these?

[Bert Johansen]

Alan, in a word, no. The crimper you should purchase is considerably more expensive, and will have (typically) three color dots--one for each wire/crimp you are using. The color coding is red, blue and yellow. For 220V you will be probably be using 10-gage wire and will use yellow, if I remember correctly. When you purchase the crimps they will identify what gage wire they are for.

[john tomljenovic]

You want one of these...

[Randy Denby]

Just an FYI...always put the slotted side of the crimp connection towards the round part of the crimp tool.

[Alan Tolchinsky]

Just an FYI...always put the slotted side of the crimp connection towards the round part of the crimp tool.

Randy, Is the slotted side of the crimp where the seam or weld is in the crimp?

[Bill Wyko]

You want one of these...
These are made by Klein tools. The other option is to solder & heat shrink.:)

[Bert Johansen]

Actually, I prefer this type. Easier to use and gives consistent results. This particular one is from circuit specialists (www.circuitspecialists.com) -- Part Number: HT-303 Price: $23.00. I have no affiliation with this company, nor have I ever purchased anything from them. I just found them on Google.

[Randy Denby]

Randy, Is the slotted side of the crimp where the seam or weld is in the crimp?

Alan, yes, where the seam is. .....This is one of those times when its awhole lot easier to show than tell. On most crimp connectors, the end where you slide the wire into has a seam or slightly open where it rounds back into itself. Always put this side into the round side of a crimping tool. This way it will force the connector together at this point instead of trying to splay open.
I hope I explained it ok
Randy

[Alan Tolchinsky]

Randy thanks. I get it and will be doing it the right way. I appreciate the explanation. Alan

[Alan Tolchinsky]

Thanks again for all the help on this. I'm going to buy a good pair of crimpers tomorrow.

[Randall Davis]

Hi All, Well great news! I just passed my rough in spection of my shop wiring. I've done it all in EMT conduit with a subpanel and using all 20 amp circuits. The inspector noted one thing on the rough in though. He told me it was not up to code to have stranded wire wrapped around a screw. He was talking about my box ground wires but it applies to all connections. He said you needed to have crimp on connectors. I don't like doing those connections and feel they are not real secure(at least the way I do them).

Any other ideas on terminating stranded no. 12 wire on a screw? Or should I just learn how to do crimp ons better. Thanks!


you don't need crimpers or connectors, your conduit is the ground and the outlet needs to be grounded to the box. you can get solid copper ground pigtails with screws at HD or any other electrical supplier for about 2-$3 a dozen. you should be installing 20 amp outlets (also at HD) and as somebody already mentioned they come with a clamp style screw for the stranded wire.

[Randall Davis]

Actually, I prefer this type. Easier to use and gives consistent results. This particular one is from circuit specialists (www.circuitspecialists.com) -- Part Number: HT-303 Price: $23.00. I have no affiliation with this company, nor have I ever purchased anything from them. I just found them on Google.


absolutely not needed in this application! save your money

[Randall Davis]

Thanks again for all the help on this. I'm going to buy a good pair of crimpers tomorrow.


save your money! read on

[David G Baker]

I use the crimp fittings that are crimped with a quality tool and add a wire nut to the wire beyond the crimp fitting. Don't know why, just another habit.

[Chris Friesen]

...you should be installing 20 amp outlets (also at HD) and as somebody already mentioned they come with a clamp style screw for the stranded wire.

Not all 20A receptacles have clamp-style screws. For instance, see: https://www.hdsupply.ca/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10051&catalogId=10051&productId=28822&parentCategoryId=10310&categoryId=10551
(https://www.hdsupply.ca/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10051&catalogId=10051&productId=28820&parentCategoryId=10310&categoryId=10551)

[Alan Tolchinsky]

All my 110 v. outlets are 20 amp with screw clamp type connections. Man they make life easier. At this point I'm thinking, as suggested by Randall, of using solid wire pigtails to attach to screws on my 220 receptacles and box grounds. This would get around using crimped connections. It's not that crimps would be that hard to do but it just looks like a simpler way of doing the job. Thanks to all who replied to this post.

[Alan Tolchinsky]

save your money! read on

Thanks Randall, that sounds like the way to go. See my last post. Alan

[Dave MacArthur]

I had heard/read somewhere that the gauge of wire used for the ground, such as that between the receptacle and the box, could be 1 less than the circuit. Anyone know if that is true? So, for Alan, say he ran 20A in his EMT using 12ga wire, could he use 14ga for the pigtails? I ended up short and did this in 2 boxes, just wondering if it was ok...

Good work on the inspection Alan, one small find is pretty good results!

[Richard Butler]

. He said you needed to have crimp on connectors. I don't like doing those connections and feel they are not real secure(at least the way I do them).

Any other ideas on terminating stranded no. 12 wire on a screw? Or should I just learn how to do crimp ons better. Thanks!

You need a quality crimper and connectors. Properly crimped, the connector to wire junction is gas tight and it doesn't get any better than that. I have had people claim that soldering afterwards assures a good connection but tests have shown that the solder doesn't penetrate. Look at it this way, If it is good enough for aircraft, ocean going ships, and diesel locomotives, it is good enough your your shop.

[Randall Davis]

You need a quality crimper and connectors. Properly crimped, the connector to wire junction is gas tight and it doesn't get any better than that. I have had people claim that soldering afterwards assures a good connection but tests have shown that the solder doesn't penetrate. Look at it this way, If it is good enough for aircraft, ocean going ships, and diesel locomotives, it is good enough your your shop.

absolutely overkill! unless you have an amphibious flying shop?

[paul wiser]

according to nec you should use solid wire for grounding a circuit. ideal makes a splice cap that crimps on the ground or other wire. they have insulated caps for the splices. stranded wire does not crimp particularly well. get a good pair of wire crimpers (klein or equal) and you won,t have a problem

[Rob Will]

I had heard/read somewhere that the gauge of wire used for the ground, such as that between the receptacle and the box, could be 1 less than the circuit. Anyone know if that is true? So, for Alan, say he ran 20A in his EMT using 12ga wire, could he use 14ga for the pigtails? I ended up short and did this in 2 boxes, just wondering if it was ok...

Good work on the inspection Alan, one small find is pretty good results!

Around here, we can't downsize the ground unless the conductors are 10ga or bigger. Personally, I install a ground equal to the largest conductor in the conduit.

Rob

[Jason Roehl]

Rob, so you can't use standard Romex for wiring, either? The ground in Romex is always undersized that I've seen. (I know...we're talking about conduit here, but it's the same principle). I'm curious as to why they would make that particular change to the NEC.

[Art Mann]

according to nec you should use solid wire for grounding a circuit. ideal makes a splice cap that crimps on the ground or other wire. they have insulated caps for the splices. stranded wire does not crimp particularly well. get a good pair of wire crimpers (klein or equal) and you won,t have a problem

I know this is a minor point, but I must disagree with the highlighted statement. A typical automobile will have literally thousands of crimps to pins and lugs like what the OP is asking about in the wiring harnesses. Crimps are never soldered. The connections last for decades in an incredibly harsh environment. The OP will have absolutely no problem making a good reliable connection with a good crimp tool and technique. I know this because it has been my job in years gone by to test the integrity of automotive harness wiring.

[Rob Russell]

according to nec you should use solid wire for grounding a circuit. ideal makes a splice cap that crimps on the ground or other wire. they have insulated caps for the splices. stranded wire does not crimp particularly well. get a good pair of wire crimpers (klein or equal) and you won,t have a problem

Paul,

If you're going refer to the NEC, you should be able to cite it. I think that you'll find that there is no such requirement in the NEC to use solid conductors for equipment grounding conductors (EGCs). If there were such a requirement to use solid conductors, it would effectively limit the size of conductors able to be used as EGC's and therefore the size of circuits. Why? Solid conductors aren't available past #8 or #10 - try to find a #4 solid conductor (minimum copper EGC for a 300 amp circuit).




I had heard/read somewhere that the gauge of wire used for the ground, such as that between the receptacle and the box, could be 1 less than the circuit. Anyone know if that is true?


Dave,

Table 250.122 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment, specifies the smallest conductor you can use for an EGC. It's based on the overcurrent protection for the circuit, aka breaker size.

To summarize the table (assume copper conductors), here's a list of circuit sizes and minimum required EGC size.

15 amps - #14
20 amps - #12
30 amps - #10
40 amps - #10
60 amps - #10
100 amps - #8.

So, once you hit 40 amps, the EGC can be smaller than the current-carrying conductors (CCCs). As the circuits get larger, the EGC can actually be more than 1 size smaller than the CCCs. For example, a typical 100 amp circuit run using copper THHN/THWN individual conductors would need #3 for the CCCs but the EGC could be as small as a #8 which is several sizes smaller than #3.

Rob

Rob

[Randall Davis]

Rob, so you can't use standard Romex for wiring, either? The ground in Romex is always undersized that I've seen. (I know...we're talking about conduit here, but it's the same principle). I'm curious as to why they would make that particular change to the NEC.

This is not accurate information, the ground and current carrying conductors are the same size in non metalic sheathed cable (romex)

[Alan Tolchinsky]

according to nec you should use solid wire for grounding a circuit. ideal makes a splice cap that crimps on the ground or other wire. they have insulated caps for the splices. stranded wire does not crimp particularly well. get a good pair of wire crimpers (klein or equal) and you won,t have a problem


This doesn't make sense since this would mean you couldn't use stranded THHN wire in a circuit. All my wire is no. 12 stranded THHN and the inspector had no problem with it. The only thing he asked was to use crimp on connections for terminations on screws. I did that for the box grounds and used "screw clamp" type outlets for both 120 volt and 220 volt circuits. The "screw clamps" work well with solid or stranded to connect to the outlets. And the crimp connections I've made with stranded wire cannot be pulled apart with a pair of pliers. With all due respect I have to question your information here.

[Bill Brady]

You will get a better job with the back wired receptacles and just use the crimps for the ground connections. When using the crimps for the hot and neutral connections sometimes this makes the receptacle difficult to fit in the box without putting a strain on or pinching the wires.

[Randall Davis]

You will get a better job with the back wired receptacles and just use the crimps for the ground connections. When using the crimps for the hot and neutral connections sometimes this makes the receptacle difficult to fit in the box without putting a strain on or pinching the wires.


every time you use the crimps in this situation you make the taks more difficult that it needs to be.

[Randall Davis]

You will get a better job with the back wired receptacles and just use the crimps for the ground connections. When using the crimps for the hot and neutral connections sometimes this makes the receptacle difficult to fit in the box without putting a strain on or pinching the wires.


every time you use the crimps in this situation you make the task more difficult that it needs to be.

[Alan Tolchinsky]

You will get a better job with the back wired receptacles and just use the crimps for the ground connections. When using the crimps for the hot and neutral connections sometimes this makes the receptacle difficult to fit in the box without putting a strain on or pinching the wires.


That's just what I did. I got all my outlets with "screw clamp" terminals. So no crimp ons needed there. But some of these outlets didn't have "screw clamp" terminals for the grounds. For these I did crimp on connections but there weren't that many. I made sure when I crimped they were very tight and couldn't move with pliers pulling on them hard to test. All my circuits work including the GFI test and I'm all done and waiting for final inspection.