Insulation Displacement Connectors 2

[DReimer]

I'm with an OEM manufacturer of industrial machinery, and we are always looking for ways to improve productivity and lower costs (well, duh!).

One area that I see great potential for time reduction is in our electrical control panels. Our typical panel contains a small PLC, a motor contactor or small VFD, a couple relays, some fuses and a bunch of terminals for connecting sensors and pneumatic valves.

I've seen demos of insulation displacement type terminal blocks where there is no longer the need to strip and/or crimp every wire. This has great potential for time savings in our panel builds.

My question is this: is anyone in North America actually using these things on industrial machinery? My big concern is customer acceptance. Are they perceived as light duty? Is there an inherent mistrust of such a device?

Any feedback is appreciated.

Thanks,
Dean

 

[IRstuff]

Insulation displacement is, I think, by definition, a permanent installation. Any change requires removal from, and possibly damage to, the connector itself.

TTFN

 

[ScottyUK]

My opinion as an end user of these kind of panels:

IDC connectors are fine on ribbon cable. They are a pain in the neck when used for anything requiring maintenance rather than exchange of whole assemblies. They make things easy and cheap for the panel builder, but harder for the maintenance teams. If the purchaser also has to maintain the equipment, they might be put off.

For power terminations I think IDC and the spring clamp terminals which are also used are too prone to melting under overload, where a 'proper' terminal would have probably survived. This is usually at the most inconvenient time imaginable. Terminals are frequently the only bit of the panel that the user interfaces to. Making that interfacing harder will give them an incentive to buy a panel from somewhere else.

Perhaps I'm a Luddite, riding round in my square-wheeled cart, afraid of technology. I still don't like these newfangled terminals though!

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If we learn from our mistakes,
I'm getting a great education!

 

[jraef]

I used to have a panel shop and tried the ones from Wago. We sent them out on a project at Boeing. All of our "savings" went out the window on the first field service call. We had to make changes in the field, it was a nightmare. Even adding wires into the spare terminals required the special insertion tool, which was never available. Boeing insisted that we yank them all out and replace them with conventional terminal blocks. I never considered them again, and Boeing now has a standard spec saying that nobody will use them on panels coming to Boeing facilities.

I would suggest investing in those simple strippers that can go at each wiring station. You just take the end of the wire and shove it in, pull it out and it is stripped and even twisted if you want it. Here is an example of what we used. It represented an up-front investment, but saved on installed cost in the long run when we were doing a lot of panels.

http://www.eraser.com/catalog.cgi?mode=details&product_id=1470

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla

 

[DReimer]

ScottyUK and jraef: thanks for the feedback. Exactly what I was looking for. I think you both have confirmed my trepidations about the terminal blocks.

We sell a lot of our equipment into Fortune 100 companies, and I would hate to put in terminals that raised the ire of our valuable customers. I suspect Boeing might not be the only large company to ban them.

My understanding is that these terminals are popular in the telecom industry, which makes sense when terminating 1000 conductors at a shot in a locked, underground, room with little need for maintenance by end users.

jraef: thanks for the link. I've seen another brand of wire stripper before, but I haven't seen this one.

 

[felixc]

In the telecom industry, the maintenance people can carry lots of tools with them. The environment is usually clean, and not prone to vibrations. In these conditions, IDC or cage clamp connectors can do the job properly.

 

[DanEE]

One other consideration that hasn't been mentioned above is whether your panel operating environment will include significant temperature cycling and the worst of all.. passing thru the dew point and subsequent wetting, the bane of a lot of connector systems due to contaminant washdown into the connection.

On a personal experience (and with a long sentence to describe the environment)..... a radio repeater system located in a non temperature controlled, sealed cabinet on the communications platform 1000' off the ground on a 1300' tall TV antenna tower.. a pretty extreme temperature cycling environment.. and with some cabinet water leaks that have occurred, probably have had some dew point condensation,

I've had only one failure of the radio controller in this extreme environment, and that was an IDC ribbon connector that went intermittent.. wasn't the connector to PCB pin contact, but the IDC to wire connection that went bad..

To prevent this happening again, I pulled the cable header cover off and soldered the wires to the connector IDC.

I agree with the views expressed above that I would have concerns about IDC connector appropriateness in your operational environment.

At a minimum, if you decide to proceed with this, it would be a good idea to talk to AMP or whomever the IDC connector manufacturer is, to determine if, in their qualification testing, whether the specific IDC connector was qualified for use in your operational environment, especially if it is include the condensing dew point.

Many "computer origin" parts and connector systems are "non condensing" environment only..

As mentioned most telephone switch office environments are temperature/humidity controlled the same as computer room environments..

 

[ScottI2R]

DanEE,
I too have encountered problems (intermittants) with ribbon cables and connectors at the crimp on one of our product lines. It is now SOP to suggest that the customer check these when I am providing telephone support. It is also one of the very first things I do when I travel to a customer for trouble with these older units. I'm just glad these are not a quarter mile up in the air! Kinda like terra firma myself.....

In a hundred years, it isn't going to matter anyway.

 

[Skogsgurra]

I had an assignment this week to find out why the cart supplying coal to a coke producing plant trips intermittently. There are several frequency inverters and a S5 PLC controlling the whole thing.

The inverters have ribbon cables all over the place and they are controlled by a Multibus II system in a rack with a solderless (press-fit) backplane.

"Everything" except the ribbon cables and the card cage have been replaced by people that went there before me and I think that replacing either the whole system or cables plus card cage is the right way to go. Probably best to change cables and cage first and then the system (delivery time issues).

The environment is gas (coming from the coke furnaces), dirt and vibration. Not much temperature change and (probably) a relatively constant humidity - not condensing, that's for sure.

We do not know if replacement helps. It will take place this week-end or next week. I will be back with the results when we have evaluated it for a while. t will take several months before we know for sure if it helped.

Gunnar Englund

http://www.gke.org

 

[ScottyUK]

Skogsgurra,

I suspect you probably have noticed that Cokeworks often have nasty emissions in the air - but have you investigated sulphur attack on silver plated connections? Sulphur make silver a lovely shade of non-conductive matt black. Could this be a contributor to the problems?



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If we learn from our mistakes,
I'm getting a great education!

 

[DanEE]

Been too many years ago to remember percentages, but our accelerated life testing chamber used trace amounts of hydrogen sulfide and chlorine gas with temps in the '90s at high humidity to pretty accurately show full product life performance in corrosive environments.

Significant corrosion of plated metals and degradation of plastics used in typical computer products occurred in the 8-12 week test cycle in this environment.