# Terminal Blocks: Allowable usage ?



## telsa (May 22, 2015)

Too expensive, too slow.


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## 99cents (Aug 20, 2012)

Ideal makes Buchanan strips.


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## glen1971 (Oct 10, 2012)

I've seen them used on the low voltage (24vdc) for control wiring. Sometimes mounted on a plywood backplate, adjacent to a Control Panel, or on the back side of racks and panel controllers for low voltage. 
From their site, it looks like they are available up to 600 volts, and 75 amps. Can't say how I can see that being fun to terminate, or allowed without being in an approved junction box.
https://www.waytekwire.com/products/1440/Terminal-Strips/


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## Southeast Power (Jan 18, 2009)

I wouldnt tape it up and stuff it in a junction box. Some old electrician like me would come along and cut it out and replace it with wire nuts.
Now,
If it were inside of a cabinet and I see wire nuts, I would install a TB like that and throw out the wire nuts.


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## splatz (May 23, 2015)

Terminal blocks - the strip type and the european style chop block type - are available listed for 300V and maybe 600V and I think usually 30A. There are power distribution blocks available for much bigger wires and amps. 

https://idealind.com/content/dam/el...es/Barrier Strips/BarrierStrip-dimensions.pdf

There is nothing stopping you from using them in a junction box. However you're not supposed to let them dangle, they are supposed to be screwed down. At that point they're not really any good in a small box, it's a pain to get wires in. They may be useful in some situations. For example if you're upgrading a service and turning the old panel into a junction box, it's a nice neat way to splice the old wires to an extension to the new panel location. 

You may be allowed to chop the chop blocks and use them like a wire nut to splice. I have considered using them to splice short wires for electric heat. I don't quite trust a Wago for that, but they're so short it's hard to make a good wire nut splice.


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## 99cents (Aug 20, 2012)

A 10104 JB can be cheaper than a 4 11/16 with an extension ring. The strips aren’t that much money. The cost difference is the back pan.

The usual drill for a splice box is to mount a 4 X 4, stuff it full of wire, hope the wire nuts stay on and hope the inspector doesn’t see the bulge in the cover. Then you turn on the breaker and hope it doesn’t explode. At least that’s what I see way too often.


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## Navyguy (Mar 15, 2010)

I use a terminal block where I would expect to do testing / troubleshooting. So for me that is a control panel or some sort of distribution box where there might be a transition from one type of wiring method to another (multiple conduits to multi conductor teck90 perhaps). I would not expect to see that in a standard junction box, especially in a residential or small commercial installation.

Cheers

John


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## 99cents (Aug 20, 2012)

Navyguy said:


> I use a terminal block where I would expect to do testing / troubleshooting. So for me that is a control panel or some sort of distribution box where there might be a transition from one type of wiring method to another (multiple conduits to multi conductor teck90 perhaps). I would not expect to see that in a standard junction box, especially in a residential or small commercial installation.
> 
> Cheers
> 
> John


Let’s say you have a 12C12 Teck coming into a JB along with another five #10’s piped in. There are a total of ten AC90’s leaving. What would you do, John?

This is not hypothetical  .


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## bill39 (Sep 4, 2009)

There is probably an arbitrary maximum number of wires, but if that number is exceeded then terminal blocks should always be used when doing control wiring. Anything else is a hack installation.

Also install wire numbers unless the color coding of the wires is sufficient.

Educate the customer that any additional cost for terminals & larger enclosures will pay off later when troubleshooting or replacement of components......and that time will always come.


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## Navyguy (Mar 15, 2010)

99cents said:


> Let’s say you have a 12C12 Teck coming into a JB along with another five #10’s piped in. There are a total of ten AC90’s leaving. What would you do, John?
> 
> This is not hypothetical  .


This is what I would do I think... or something similar










Cheers
John


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## glen1971 (Oct 10, 2012)

99cents said:


> Let’s say you have a 12C12 Teck coming into a JB along with another five #10’s piped in. There are a total of ten AC90’s leaving. What would you do, John?
> 
> This is not hypothetical  .


Myself, I'd use a Hoffman A20H1606GQRLP (20"x16") or A20H2006 (20"x20") Junction Box, with Weidmueller WDU6 terminals, on TS35 rail, 2"x 2" panduit with cover on each side, and ground bar on the bottom of the back plate.. I like the GQRLP models, as they have decent latches and are fairly well built and readily available in this part of the country.


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## boot (Mar 1, 2013)

Thanks for the replies! I'll be reading them and responding. I didn't get an email alert, so I had thought my thread was a dud and just realized you guys responded.


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## boot (Mar 1, 2013)

As a residential grunt, seeing 10104, A20H1606GQRLP and 12C12 TECK , I was forced to resort to the Googler. That said, I've seen plenty of 10104, but didn't know the part number. Usually, I can impress my co-workers by rattling off the part numbers of the various *blue * (shriek) colored boxes :wink: I'll have to up my game to compete with the commercial sparkies round these parts.

That said, the general consensus I am feeling here is that those terminal blocks are best left in controller cabinets. But if I'm feeling wild, I should at least secure the block if I am going to use it- fair enough; though at this point I am not inclined to use them.

This train of thought started when I opened up a B120A with 8 cables going into it. I thought, I'd sure like to clean this up, is there a better way than wire nuts all over again inside a bigger JB? I guess the easy answer is, no, not if I want to sleep at night. I just really envy the UK jboxes with their integrated terminal blocks.

I understand I can minimize the length of wire that gets ruined by a good wire nut twist that doesn't propagate down the length of the conductor, but wouldn't it be nice if none of it had to go waste? Once you have to undo that twist, I usually just cut it off. I hate re-straightening once twisted copper. 1 of 10 times it just breaks off , which probably means 1 out of 5 of the re-twists that don't break, were probably one wrong look away from breaking too.

Wires also take up more volume and resist being folded into JBs once they have a twist. I'm not saying this aspect of my job is a big surprise, I'm just asking, why have we been doing it the same way for 100+ years? Not wire nuts per se, but just twisting copper into plastic deformation.


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## Bird dog (Oct 27, 2015)

Wirenuts haven't been around for 100+ years. Solder & friction tape have been used. Those blocks are used for specific purposes.


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## boot (Mar 1, 2013)

Bird dog said:


> Wirenuts haven't been around for 100+ years. Solder & friction tape have been used. Those blocks are used for specific purposes.


True, hence my disclaimer targeting the act of twisting in particular. The soldered and taped connections are always in magnificent shape when I get into them, however, they are still twisted prior.


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## bill39 (Sep 4, 2009)

Bird dog said:


> Wirenuts haven't been around for 100+ years. Solder & friction tape have been used. Those blocks are used for specific purposes.


I certainly cannot disagree with your comments but do not understand your what your point is.

Please expand on it


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## electricguy (Mar 22, 2007)

We have to leave 6 inches of free conductor starting at the face of the box no way would i want to deal with terminal strips trying to stuff that back into the box


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## GladMech (Sep 18, 2020)

I hate wire nuts. For my personal use, I love the "eurostyle" terminals both as small junctions screwed down and as substitutes for wirenuts. They ARE officially "touchsafe", so in my mind are functionally equivalent to a floating wirenut. However, I am not sure if the code addresses them at all. I have been tempted many times to use them in small enclosed transformers.


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## Darr (Aug 19, 2016)

GladMech said:


> I hate wire nuts. For my personal use, I love the "eurostyle" terminals both as small junctions screwed down and as substitutes for wirenuts. They ARE officially "touchsafe", so in my mind are functionally equivalent to a floating wirenut. However, I am not sure if the code addresses them at all. I have been tempted many times to use them in small enclosed transformers.


That's what I use in potheads to wire motors. You can clip them to the size you need (e.g. 3 or 4) with flush cutters. No tape needed as long as there's no exposed conductor.
NFPA 79 prohibits use of wire nuts in motor potheads, by the way, even though you see them used all the time.
edit: referring to strips like





Molex 39100-2212 12-Pin Eurostyle Terminal Block | Waytek


Molex 39100-2212 12-Pin Eurostyle Terminal Block has a 12mm pitch, modular design, rated for 40A and 600V, and is available at Waytek Wire.




www.waytekwire.com


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