EN60204 and twin ferrules

I've seen those terminal linkers referred to as 'comb' (like hair do) , but in my world honeycomb is lots of tubes formed into hexagons. Used to keep RF and EMPs out of the cooling ducts but allow almost laminar air flow. Depending who you talk to, be aware that there may be potential confusion with the honey ;-)

Mike.

Ah yes - I know these well.

Thanks.

Dave in the Shed,

No problems sharing my thoughts, below is a image of a terminal linking assemby that I and others would call a honecombe type this being more for terminals than MCB's, but you are spot on principal is the same.

Cheers GTB

Thank you GTB - valued input once again.

I'm in agreement with everything that you've said - all pointing towards there being nothing forbidden in the use of the humble twin ferrule.

I'm unfamiliar with the terminology of "honeycomb linking assembly" but I'm guessing that you might be referring to something like this:

If that is indeed what you're referring to then it's an excellent relevant example that I hadn't thought of. The MCB commoning bar shares a lot of commonality with the concept of the twin ferrule in terms of the 60204 one conductor/two conductor quandary - marvellous stuff.

Thanks again.

Afternoon,

My understanding and interpretation over the years and as many have indicated below. The terminal design is what is important. So if a terminal is only designed for one "Conductor" then thats because the clamping mechanism has been designed to tighten and possibly lock around one single cylindrical shape in other words the pin of a cable lug or bootlace ferrule.

The wording is indicating if you had two solid conductors or indeed two pins of cable crimps or two bootlace ferrules the manufacturer cannot then guarantee with the standard that those conductors will not come loose. Whearas what I call a "Piggy Back" terminal has basically a rear and front layer so two conductors, one in each layer and hence design of terminal makes everything common.

As long as the conductor size and type and Max loads are appropriate for a twin ferrule, are prepared and inserted correctly and crimped down with the appropriate ratchet crimping tool then nothing wrong with that.

I have had a few clients that in their specs, reject twin ferrules, simply due to trying to work on a single conductor in the future. Also if the idea of the twin ferrules is to loop lots of terminals together so to form a common terminal rail I would reject that and use the terminal manufacturers own designed linking assemblies/components for doing that.

In fact if you think about it, its acceptable where using a honeycombe linking assembly that a single conductor goes in with one of the points of the honeycombe rail to make it common, but in some ways that situation is two conductors in a terminal!

Cheers GTB

Thanks for your input mapj1. Glad to hear that you're also of the same general view about this.

It seems that the general opinion amongst those who know a bit about electrical engineering is the common sense opinion that the use of a dual ferrule is just as valid as a single ferrule (subject to the usual caveats about suitability of the terminal, wire type and so forth).

In addition to all this wisdom I'm still keen to do some more digging to find anything more definitive (in the context of the interpretation of the standard).

Any more knowledge out there?

Well the key is "where the terminal is designed for that purpose." I can imagine an unlikely but possible  situation where one terminal is so close to its neighbours that a large funneled bootlace ferrule does not fit, but apart from that, if the terminal can accept ferrules, then if the strands in the tube come from more than one wire, or not, is not important- it is the ferrule that is sized  to do that.

So are your terminals suited to ferrules at all, and if so is there enough room to fit a dual entry one without collisions? In your place I might drop an email to the makers of the terminals you have in mind checking that ferrules of that style are OK.

Mike.

Hi Chris Pearson - thanks for your input.

That type of ferrule is exctly what I'm referring to. It's encouraging to hear your "one conductor" view. Do you know of any published guidance or other definitive info which supports your view? I'd really like to track down something a bit more solid so that I can effectively counter the views of the nay-sayers.

I agree absolutely.

I'm a bit of a purist when it comes to doing things correctly (like ensuring that the correct type of wire is used in a ferrule). Sometimes that purist approach is driven simply because it is right and proper from an engineering point of view (including of course from a safety perspective) and sometimes it's driven by a need to conform to the requirements of a standard or directive for compliance reasons.

My current dilemma is that I'd like to declare compliance with 60204 on a machine I'm currently designing/building but I'd also like to use twin ferrules in some locations due to space constraints. To add to the fun, the end client is pretty strict on compliance-related issues so I'd really like to have some definitive guidance in place before the finished machine gets condemned by an over-zealous client.

Still hoping for more wisdom..... anybody?

Do you mean this sort of thing? https://uk.rs-online.com/web/p/bootlace-ferrules/1788734?cm_mmc=UK-PLA-DS3A-_-google-_-CSS_UK_EN_Connectors_Whoop-_-Bootlace+Ferrules_Whoop-_-1788734&matchtype=&pla-302478546419&cq_src=google_ads&cq_cmp=9771206614&cq_term=&cq_plac=&cq_net=g&cq_plt=gp&gclid=EAIaIQobChMIjaXf7ej2-AIVCdPtCh2F2APSEAQYBSABEgL4HfD_BwE&gclsrc=aw.ds

I'd regard that as one conductor.