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DIN rail terminal block howto?

post #1 of 15
Thread Starter 
When pulling all out WHA wiring together I'm leaning toward using a DIN rail with terminal blocks to manage the transition from the in-wall wiring over to the rack mounted gear.

Is there a resource out there to get a jumpstart on planning DIN rail setups? I'd like to get a handle on just how many terminal blocks I'll need and how they'll fit into wall enclosures.

All the in-wall audio wiring it either 14 or 16AWG. Most of it it has either a 14/4 or a 16/4 running to each keypad location. From there it's either 14/2 or 16/2 depending on the source gauge. And it's only the locations with cabling distances more than 75' that have the 14AWG. So I'd only need terminal blocks to handle 14WAG max. I'll have 23 zones. But I'm probably only going to be using 18 of them. So while I'll terminate all of them in the enclosures, only 18 of them will patch over to the rack. I ran wire for possible future expansion, but honestly the locations that won't get used are trivial (laundry room, powder rooms, etc). Still, having them neatly terminated will make it easier to do something with them later.

It appears Altech has a pretty nice assortment of stuff for this. But I've not found a worksheet or workbook that helps design this sort of thing. Anyone got pointers on doing this?
post #2 of 15
I picked a manufacturer (Wago, in my case), and did a ton of reading online, from Wago and from their distributors. I also spoke on the phone to a few distributors, with specific questions.

I think Phoenix is more popular, cheaper, and more widely available, but I like that Wago has a strong history of extremely well engineered products.

It's been a while since I've had to think about this.

What I would suggest is 'feed through' terminal blocks - one connection in, one out, aka 2 conductor TB. No ground connection to the rail.



The stripped conductor end is put into one of the side holes and the connection is made with a screw terminal, in the above example. A screwdriver tightens the connection, from the front of the TB (top of the pic is the front of the TB). That is a side entry terminal block.

Front entry also available, where the conductor comes into the block from the front:



That is a 4 conductor pass-through TB, front entry.

When space is a factor, you can use double density/double decker TBs (triple density also available):



That's an example of a front entry, 2 conductor, double density TB. That Wago one doesn't use screws, but uses screwless 'cage clamps' to trap the conductors:



A tool like a mini screwdriver is introduced into the front of the TB to depress the spring, and the conductor is inserted. Then the spring is released. I had some trouble performing this - I used a mini screwdriver and not the special tool.

This pic shows a special tool used to depress the spring:



http://wago.us/service/27873.htm - commercial for Wago Cage Clamp

There are 2-3 different standard sizes of DIN rail used by all manufacturers. I remember looking at the spec sheet of the TB to determine the size DIN rail, and just ordered a length of DIN rail from the distributor. The TBs simply click onto the DIN rail. I think 1 standard size is most common, and the 'micro' and 'mini' TBs use something smaller.



For each model TB, there are 'end plates' (listed under 'accessories' usually) available. Each TB has one enclosed side and one open side - to reduce space. To finish a row, you click in this end plate to cover up the open TB. Depending on price, you could just use an extra, unused TB at the end of the row. Your distributor may make you buy a minimum quantity of end plates. Officially, you're supposed to use a block at the each end of a row that locks to the DIN rail, to keep the TBs from sliding, but mine are difficult to move, so I skipped this. End plate example:



Some fancy TBs have ground connections, point testing connections, fuses/PTCs, ICs, and other electric components.

It is easier and cheaper to use barrier strips/Buchanan blocks/barrier blocks/terminal strips, either screwed into the enclosure or onto an adapter plate:



And, as I have said previously, most people run their speaker cables all the way to the amps, without patching. Just wanted to make that clear, for others.
post #3 of 15
I'd like to add that I'm ditching the Wago DIN rail mount TBs, when I replace my rack. I need something easily disconnected and reconnected (going with panel-mount Neutrik SpeakOns).

Current:



Those are side-entry 2 conductor Wago Cage Clamp Din-mount TBs; can't recall the model #. I put an end plate between each group of 4, because I had extras.
post #4 of 15
Thread Starter 
Quote:
Originally Posted by Neurorad View Post

I'd like to add that I'm ditching the Wago DIN rail mount TBs, when I replace my rack. I need something easily disconnected and reconnected (going with panel-mount Neutrik SpeakOns).

What're the circumstances in which you need to be reconnecting things?

And was the mini-screwdriver the main problem with those TBs and the disconnects? I'd likely go with ones that used screws instead of clips, as I usually find the clips to be more of a hassle (as seems to be your situation as well).

I don't forsee rearranging the WHA audio connections with any sort of regularity. But maybe I'm missing something?
post #5 of 15
The rack is slightly blocking an electrical sub panel. I'm slightly shy of the code required 30" with the rack in place, so want to be able to quickly move it. Also blocking replacement /service of an AC unit. The sub panel is currently not live, but will be used for the future basement media/rec room (currently a playroom).
post #6 of 15
I have no idea if the special tool will be easier, but the cage clamps are touted (by Wago) as superior to screw clamps. I connected the conductors in a day, didn't want to wait for the tool. Suffered through the mini screwdriver. Not terrible, just not perfect. If I had to do it again, with cage clamps, I'd find the tool.
post #7 of 15
Thread Starter 
Thanks for all the details! That helps (and hopefully future searchers will benefit too).
Quote:
Originally Posted by Neurorad View Post

The rack is slightly blocking an electrical sub panel. I'm slightly shy of the code required 30" with the rack in place, so want to be able to quickly move it. Also blocking replacement /service of an AC unit. The sub panel is currently not live, but will be used for the future basement media/rec room (currently a playroom).
Ah, that would make a difference. I'm fortunate in that the rack and the enclosures will not be blocking anything.
Quote:
I have no idea if the special tool will be easier, but the cage clamps are touted (by Wago) as superior to screw clamps. I connected the conductors in a day, didn't want to wait for the tool. Suffered through the mini screwdriver. Not terrible, just not perfect. If I had to do it again, with cage clamps, I'd find the tool.
Hmm, but I'd wonder just how much 'better' the clamp would be than screws. With screws you can at least open all of the connections for a given cable, insert all the wires and then tighten them individually. Versus needing enough slack to get them connected one at a time with the clamp and tool arrangement. This being for a 4 conductor speaker cable. For one wire at a time I could see where the clamp would be faster as you wouldn't be turning the screw to tighten the clamp each time. For manufacturing, sure, that'd be 'better'.

Meanwhile I'll need to get started on planning just how many of the wires/terminals will fit in the enclosures, along with everything else in them.
post #8 of 15
If I was to use the non-DIN barrier terminal strips, I'd probably use crimped spade connectors with them.





It could be an extra point of failure, but it's a little 'cleaner'.
post #9 of 15
Thread Starter 
The downsides to the crimps is the added point of failure and the labor to install them. Hard to say which is worse.... no, it's the added time. It'll be enough that I'm stripping the ends off quite a few connections. Why add the time to put connectors on and then still have to screw them to the strip?

Sure, in situations like on our boat it's a no-brainer, ring terminals makes tremendous sense in that they add another layer of physical security. Granted a crimp could fail, but if a screw works loose then at least the ring hold the wire in place, rather than letting it risk flopping loose. But for a home audio setup?

Now, there's the cost factor, I'm sure crimps and strips would probably be less expensive, parts-wise.
post #10 of 15
I don't know about hooking up your Hi-Fi but this type of terminal block is used a lot in fire alarm systems. Note the captive square plate below the screw:


They make a very secure connection on a variety of bare wire ends. I've yet to see a 'stab the wire in a hole' connection or a crimp used in alarms.

EDIT: FWIW I found that one at Sears: http://www.sears.com/search=mcm%208%20position%20european%20barrier%20strip%20terminal%20strip
Edited by olyteddy - 5/8/13 at 7:53am
post #11 of 15
Thread Starter 
Sure, where you've got solid core wire, like in security or thermostat wiring, it makes a lot of sense to use a clamp-down terminal. But that's not the typical kind of wire used for audio.

The plastic euro kind (I'm sure there's probably some other, better name for them) are the kind I've used when making the 4-conductor to 2-conductor splices behind the keypads. They work pretty well for this, as the round collar and screw tends to keep the end together better than the flat kind. That and the plasic insulates the connection better than the more exposed strip kind.
post #12 of 15
I've been using Wago Lever Nuts for splicing speaker cable conductors, behind keypads. They use the same 'Cage Clamp' technology used in the Wago DIN rail mount TBs.



Very secure; tough to unlock. No reliance on screw-down connections.
post #13 of 15
Quote:
Originally Posted by wkearney99 View Post

Sure, where you've got solid core wire, like in security or thermostat wiring, it makes a lot of sense to use a clamp-down terminal. But that's not the typical kind of wire used for audio.

The plastic euro kind (I'm sure there's probably some other, better name for them) are the kind I've used when making the 4-conductor to 2-conductor splices behind the keypads. They work pretty well for this, as the round collar and screw tends to keep the end together better than the flat kind. That and the plasic insulates the connection better than the more exposed strip kind.
They actually work real well for stranded wire, too. The plate provides a rather large contact area. We have a lot of THHN stranded terminated in these and I have no doubt they'd grab finer strands just as well.
post #14 of 15
Thread Starter 
Oooo, clever inline splice connectors, thanks!
post #15 of 15
Do not use the generic terminal strips they are garbage. I have terminated hundreds of thousands of wires using din rail and blocks they work great. Only real good option to use in Heavy Industrial applications. Tweaker screwdrivers work great for din rail terminations. Also I would recommend Allen Bradley TBs ...Phoenix Comtact are also good.
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