Joe's thread on wire-nuts got me thinking (yes, that's a bad thing). What if we do what the Europeans do and start using terminal strips instead of splicing caps for some applications?

The advantage I see to this is that there is less damage to the wires being spliced (especially the cable in the box) and it's much easier to swap devices like light fixtures in and out. A deeply recessed set-screw (grub screw for those of you in the UK) holds the wires in place.

The blocks I'm talking about look like this:



I was wondering also if someone in NEC-land used these to wire in a luminaire instead of splicing caps, would they be violating any codes?

The disadvantage with these terminal blocks is that you can't pigtail a bunch of connectors together. You can only splice two wires together.

So this wouldn't work if you have to join each pigtail of a luminaire to a group of three wires each in the ceiling box. You'll need a splicing cap for that...unless there are special blocks with loop-through functions.

[This message has been edited by SvenNYC (edited 02-14-2003).]

[This message has been edited by SvenNYC (edited 02-14-2003).]

SvenNYC...i think it all comes down to the price.one wirenut. 3 to 5 cents each. but i have seen these connectors around.

SvenNYC,

When you do a fire alarm in Rhode Island these are a requirement (actually it would be more accurate to say wire nuts are not allowed) and I use them for FA work in MA too, I like the fact that it's easy to get meter probes on and for installing end of line resisters.

As I usually have some in my truck I sometimes use them for other things.

If you need to tie more then two conductors together you can buy jumpers, more cost.

But to use them for all work seems like overkill to me.

For all we talk about to twist or not to twist I think the failure rate of wirenuts is low when you think of how many are in use.
Bob



[This message has been edited by iwire (edited 02-15-2003).]

I don't think I understood that comment. You can get three (or perhaps four) conductors per side, totalling six. By the way, what's wrong with using a wire as jumper?

C-H
The one in the picture that sven posted looks exactly like the ones I use, they will fit up to #12 awg, when I do FA work it is mostly #14 awg, 2 #14s would not fit in the hole and would be a violation of the listing. I also have ones that hold up to #8 awg
The ones I get come in strips of 12 pairs (24 holes) I would call the one in the picture 3 terminals (6 holes) only 6 wires total could be landed and only 3 of the 6 are electrically connected You break off
the number you need.


When you need jumpers they are a flat piece of metal shaped kinda like a comb, you break or cut off the number of jumpers you need these will fit in the terminals along with the conducter.

Doing Fire alarm work jumpers are not needed as we do not "T" tap anything.

iwire: I'm with you now. They need to be large to accept more than one conductor. (Here in Scandinavia a special type of these is sometimes used: It has only one screw and is open only on one side.)

I am familiar with this system. Perhaps it is used in Canada- I'm told Canada doesn't allow the use of wire nuts.
These terminal strips differ from what we see in the US by coming in long "blocks"; you break off and use as many ports as you need. There are (noninsulated) "combs" that you use to jumper adjacent ports together.
Usually, the terminal strips are free-floating; that is, not anchored to the enclosure.
Some of the appliances from Europe will come with these. I have no problem in using them.

John:
If these "combs" are uninsulated, and the connectors are free floating, how are they kept from contact with the enclosure?

I have used the US type, secured to a surface, for low voltage stuff with the jumpers, for years. But, these don't move when they are fastened.

If you have to tape them up with the jumpers in, what is the advantage over wire nuts? Are there no insulated jumpers available?

Just asking the questions.

I float these in a box for FA work but as I said we do not use the jumpers.

Times I have used the jumpers it would be in a control cabinet like a compactor control or other motor control work and I would screw them down, the one in the picture has holes for this between each terminal.

Bob

Not true. Canada uses the same wiring methods and materials as the USA.

Ed

But using non-insulated jumpers defeats the whole purpose of these barrier strips that are designed to reduce and nearly eliminate the risk of contact with live terminals. Wouldn't that violate the listing?

I used a piece of this type terminal block (two sections) to attach a new flex to a clock radio recently. Space inside the plastic cabinet was very tight and it was a more compact solution than wirenuts.

[This message has been edited by SvenNYC (edited 02-19-2003).]

{Scratches his head}

Cubby964:

I'll echo iwire and SvenNYC: You can only use uninsulated "combs" with properly secured terminal blocks, in my humble opinion. (I've never seen "combs" in the stores, although they are shipped with some equipment which can be connected for both single and poly-phase.)


I think wire nuts are not allowed in appliances: Vibration is not good for the contact between the wires, if I have understood things correctly. In Europe, you find the aforementioned terminal strips on everything from ceiling lamps to ranges. The Brits also use them instead of wirenuts, but I suspect that is just an excentric British habit.

Does anyone know if the terminal blocks shown are UL Listed?? Or are they a Recognized Component. If the latter then they cannot be used off-hand in place of Listed connectors, only as a part of a Listed product after evaluation of the total product. Also, if Listed, are they required to be secured in-place and what is the tightening torque for the terminals?

Here is a site from Ideal that shows listing and specs. I can not get the link to bring you directly to the page but use it, then click on "Terminal Strips" then click on "Barrier Strips"
http://www.idealindustries.com/wt/TerminalBlocks.nsf

Bob

[This message has been edited by iwire (edited 02-19-2003).]

I stand corrected regarding the use of wire nuts in Canada- I was relying on the two "electricity" books in the Time-Life home improvement library for that bad info!
I also forgot to mention that contact with the enclosure was not an issue in the installations that I saw, as the "enclosure" was a simple round plastic box.
As for the listing, UL and the NEC are American institutions; while they have their good points, not everyone does things "our" way, or waits for us to develope things for them. In the places where I saw these strips used, there was a general way of doing things that was simply crappy- though I did like the "break to size, jumper with combs, anchor if you want" style of terminal strips.

Jes, I took a look at the strip I have and it has the UR seal, not the UL seal. So I believe it's just a Recognized Component.

My strip also bears the Semko/Nemko/Demko, CSA and KEMA-KEUR seals.

I think I'll continue sticking with wire-nuts/Scruits/Marrettes (whatever you prefer to call them) for American type installations.

[This message has been edited by SvenNYC (edited 02-22-2003).]

I have used the barrier strips mounted inside of large j-boxes for multiple branch circuit connections where the possiblilty of future re-circuiting is likly. It sure makes it easier for trouble shooting and remodels in large commercial buildings. The key to success is to label all of the load and line sides and conductors.
http://www.idealindustries.com/wt/TerminalBlocks.nsf