terminal block technology

MNJ96 · Mar 1, 2006

hi everyone

i am about to order terminal blocks for a large project and i am trying to get a standard terminal block system for our facility . we currently have some of everything . i have been looking at the allen bradley 1492 series with common accessories similar to phoenix contact clipline . ab is still a little behind pc in the jumpers all clipline series jumper together no matter the size or connection method of the terminal block ab only does this in their smaller models i would like to use ab . but my question is in general speaking what is the best type of block spring clamp , screw type or insulation displacement . standard machinery low vibration

TimWilborne · Mar 1, 2006

I used to only use screw types, but then I ran into a machine that had bad harmonics(not vibration) that kept loosening the screws. Went to the spring clamps and they worked great. The newer spring clamps are a lot better than they used to be also. Most will clamp down on a single strand of wire and take a lot of effort to pull the wire out without releasing.

Personally I like Phoenix and Entrelec. The last batch I ordered was Phoenix. But I would stay away from the terminals with all the bells and whistles and if you use the insulation displacement make sure a regular terminal screw driver will operate the terminal.

TimothyMoulder · Mar 1, 2006

Check Automation Direct. Great selection, great price. I used to use Phoenix Contact, and switched.

TM

elevmike · Mar 1, 2006

We use the terminals from Automation Direct. Fair pricing, good variaty, and good quality. They mount on a DIN rail so we're not dealing with a bunch of different mounts for components and terminals etc...

MNJ96 · Mar 1, 2006

are the spring type best used with or without a ferrule i have seen them both ways

PhilipW · Mar 1, 2006

Recently I was involved in upgrading a pump station that was about 20 years old. All the multicore landed on about 1000+ screw terminals in the control cabinet. We are talking about zero vibration, totally benign temperature, etc....and yet in that 20 years ALL of those screw terminals could now be tightened another 2-3 turns. In numerous cases the old wire just fell out. Over time the copper just relaxed....and there is no way for screw terminals to counter this.

I'm a convert to springs or IDC's as a result of seeing this.

miller_02 · Mar 1, 2006

the problem with screw terminals is the heating and cooling of the metal, copper is bad, aluminum is even worse, I do agree with the though of staying away terminals that require special tools to operate them, they are a pain, much easier to use ones that require a standard screwdiver

Binaural · Mar 1, 2006

Weidmuller Zic-Zac terminals are pretty damn good and can be operated with a standard screwdriver. I often use them whenever a cabinet is too tight to take standard single-height terminals.

MNJ96 · Mar 1, 2006

which are best

PhilipW said:
Recently I was involved in upgrading a pump station that was about 20 years old. All the multicore landed on about 1000+ screw terminals in the control cabinet. We are talking about zero vibration, totally benign temperature, etc....and yet in that 20 years ALL of those screw terminals could now be tightened another 2-3 turns. In numerous cases the old wire just fell out. Over time the copper just relaxed....and there is no way for screw terminals to counter this.

I'm a convert to springs or IDC's as a result of seeing this.

phillipw

between springs and idc which do you prefer as an across the board terminal and used for many applications

brucechase · Mar 2, 2006

Beware the IDC

I also have changed from the screw to the spring. I use the AB 1492-LD3C which is a 2 level commoned block and then I only use 2 of the terminal (which gives me 50% spare points without real estate). After looking at all the IDC terminal strips, I noticed that there was some fine print in most (some the salesman didn't even know about) that stated if you used the IDC and then remove the wire, you will have to cut off the part where the insulation was pierced and put in a uncut piece. That means every time you take out the wire, you loose about 1/8" off the end. Do this a couple of times and it will then be too short. Also, since the IDC has to go in the front, it doesn't make a neat looking panel at all.

JesperMP · Mar 2, 2006

Also, since the IDC has to go in the front, it doesn't make a neat looking panel at all

Not as neat looking, but it is an advantage that you can easily see the hole where you have to put the wire. It is the same for spring terminals (aka cage clamp) which I prefer for several reasons, the easy access from the top being one of them.
I just so hate to fumble in the dark when inserting a wire into a conventional screw terminal, in particular if it is sitting low and the ligthing is not so good.

MNJ96 · Mar 2, 2006

thanks

for all the reply i am going to go with the ab spring clamp . but i still want to know everyone recomendation of to use ferrules or not ?

TimothyMoulder · Mar 2, 2006

Use ferules

TConnolly · Mar 2, 2006

Ferrules are a major pain in the butt. Nevertheless, I use them and recommend them. Spend the money for a good crimper.

Steve Etter · Mar 2, 2006

I definitely agree: use ferrules. Three good reasons. 1) You can prevent stray strands more easily, 2) the crimping of the ferrule gives a ready-made catch for the spring and 3) visually you can quickly detect any wire might not be fully inserted.

Steve

terminal block technology

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