din rail terminals

[Robin Spark]

Hi guys,

just wanted some advice on what is needed with regards to set up for din rail terminals.

If its just an earthing bar, then I know I will need adaptable box, din rail, selection of terminals.

However just need to make sure are they all electrically common through the din rail and do I need end cap terminals?

Also any preference on manufacturer?

Cheers

 

[NozSpark]

It all depends on what you're using them for IMHO

Earth ones connect "electrically" to the DIN rail, so if you're using them to extend from an existing DB location to a new one then it could play havoc with your r2, or R2, tests (parallel paths!)

 

[steptoe]

you need end caps no matter what, there will always be one end exposed,

other than that DIN is a standard form.

'DIN' is a designation/standardisation AFAIAA , if I understand it correctly, have a look at your pliers, its like VDE , kind of.

 

[kerching]

Not sure what you mean, sorry.

Din terminals will be isolated from the din rail unless they are earth terminals. The earth terminals actually clamp onto the rail and there is continuity from the terminals to the din rail [if you like this is a common earth bus]

IF however you want to make a set of terminals 'common'.....ie one feed to a terminal which is then common to a number of adjacent terminals then you fit 'screw in links/jumpers' from terminal to terminal. These usually fasten on top of the terminal so that the cable are not compromised/used-up.

There are 2 main types of Din ter...symmetrical and asymmetrical

The first fits on a top hat profile rail and the second onto a 'G' shaped rail. Some terminals will fit both formats.

End stops are useful as they stop the terms swollocking about, I tend to use the earth terminals as end stops as I usually have them in stock.

Loads of makes, I just buy whatever is on offer....Eldon, Wieland, whatever

You can also get double layer ones, fused ones, relay base ones etc etc etc.....be careful now, it's a minefield out there.

Mine usually come from t'interwebnet or CPC as it is just down the road................. :coat

 

[kerching]

Siemens Terminals are insulated both ends (depending which ones you purchase) Although most are uninsulated one side

I like the Wago ones out of preference

I have in the past used clip on end plates to insulate the 'open side' , but the last batch I bought [about 500 of them, 6mm] were fully enclosed; so I just put earth terms at each end..... :coat

 

[Robin Spark]

Thanks for the speedy replies, just went to look on cpc but site is under maintenance at the moment. Basically might be wiring up a dental surgery in the new year which might need an earth referencing bar with supplementary bonds taken to it etc. Looked on the internet and a proprietory one is a few hundred quid which is basically two copper earthing bars in an enclosure, so was thinking I could make up something a lot more cost effective.

 

[Robin Spark]

Then a proper 1/4" square bar with the relevant terminals would be better Ill post a pic tomorrow for you - much better than DIN rail terminals

Ok thanks for that

 

[kerching]

Then a proper 1/4" square bar with the relevant terminals would be better Ill post a pic tomorrow for you - much better than DIN rail terminals

Agreed! I wouldn't use a Din rail for a marshalling bar............ :coat

 

[Sidewinder]

Robin,

There is a lot of other things that you will have to consider for the dental surgery come next year, and also 7671 is only part of it.

You will need to refer to the HTM's also, though it seems at this time the HTM's have been rolled into 7671 we don't know if the HTM's will be further upgraded.

HTH

 

[Robin Spark]

Robin,There is a lot of other things that you will have to consider for the dental surgery come next year, and also 7671 is only part of it.

You will need to refer to the HTM's also, though it seems at this time the HTM's have been rolled into 7671 we don't know if the HTM's will be further upgraded.

HTH

Yes agreed, I have been looking at HTM O6 and Meigan, alongside Special Locations guidance note (now I know the reason for all of the headaches recently!).

After speaking with the practice manager and proprietor/ dentist I think as far as I can understand a lot will depend on what procedures will be taking place.

Currently they dont do any major surgery or general anaesthetic, also everything is air/water or battery powered tools that they use so no risk of shock to patient.

The x ray machine has its own safety isolating transformer.

so with all of this in mind, I am thinking that i could treat as a Class 0 installation and not go through alot of the extra requirements for earthing etc.

However, if they get a contract with the local PCT to carry out more major procedures then installation requirements will change.

 

[Robin Spark]

Have you got the BGB as that has a section on medical locations and is a virtual copy of then HTMIll post a piccy of my earth bar system tomorrow although its used for panels and im sure Manator who does this alll the time has a decent method

Yes got BGB from Elex show recently in Coventry. Would be good if Manator could attend the forum and give some input

 

[Manator]

Very sorry guys but I do not broadcast my holidays, and as I am touring it is often hard to catch up.

The main problem with any dental surgery is the fact that they could do NHS. This is often overlooked by private dental surgeries, and the problem arises when they actualy treat a NHS patient. Medical locations has just been added to BS 7671, and just as Sidewinder says in his post, is almost a carbon copy of the HTM06.

I started doing hospital refits, and the majority of the dental suites I now do are high risk hospital installs, which is not quite like your local dentist as such, but the bonding is vital, and the increased cable sizes required for the disconnection times.

The earth bars that I use are subdivided into solid double terminal connectors. Depending on the "run", I tend to use at least 10mm from the MET, any interconnector is then in 10mm, and all the bonding in the room is 6mm, if the distribution board is a good way away, I up the main earthing to 16mm, and have used even 25mm or above dependant on the calcs. The ERB should be visible, but in private practices this is not always possible, so as long as you note in your drawings and certificates its position, then it should be fine.

 

[Robin Spark]

Hi Manator,

hope you had a good one, but quite rightly dont pre advertise your planned holidays for some low life to take advantage, countless times i see people updating their status on facebook with " I'm waiting at the airport etc!"

can I just clarify few things:-

1. Does it make any difference if the patient is private or nhs because dont all medical practices come under CQC and PCT? So in effect we could be saying that NHS patients would get a safer environment.

2. Can you recommend manufacturer of ERB that you have used and approximate cost if you know or remember?

3. Do you still think the extra bonding is a requirement and all the extra guidance to be followed for a normal dental practice, because from what I can gather no applied electrical parts are going to be inserted into the patients mouth. When I spoke to the dentist he showed me all of the implements they are all air/water/battery powered.

I want to make sure I get these things right as last refit he had a builder and his spark do the work and I was left to sort the problems out later on. So it would be better if I can get everything sorted to required standard from initial design onwards so to speak.

thanks

 

[Manator]

Hi Manator,hope you had a good one, but quite rightly dont pre advertise your planned holidays for some low life to take advantage, countless times i see people updating their status on facebook with " I'm waiting at the airport etc!" thank you, I am having a wail of a time

can I just clarify few things:-

1. Does it make any difference if the patient is private or nhs because dont all medical practices come under CQC and PCT? So in effect we could be saying that NHS patients would get a safer environment.This used to be the case in many situations. The PCT (Primary Care Trust) are the regulators, and are the people who deal with any grant works involved, this often entails NHS patients, and they require the dentist to accept a number of patients, and be open for business in a defined timescale.

2. Can you recommend manufacturer of ERB that you have used and approximate cost if you know or remember?I always make my own, this is because the hospital type enclosures have a clear screen, and in most practices would look awfull. I normally put the ERB above the door, external to the surgery, this is so that it can be inspected without having to enter the surgery.

3. Do you still think the extra bonding is a requirement and all the extra guidance to be followed for a normal dental practice, because from what I can gather no applied electrical parts are going to be inserted into the patients mouth. When I spoke to the dentist he showed me all of the implements they are all air/water/battery powered.The main problem here is the contact voltage, and the required disconnection times, I have not had a problem so far to be truthfull. However, the number of sockets allowed on any circuit is very much restricted, I have had to add up to 10mm earth bonding to the socket circuits in order to keep within the strict guidlines. very often it is very hard to put down a R1+R2, or r1+r2 reading, because the readings are lower than 0.1.

I want to make sure I get these things right as last refit he had a builder and his spark do the work and I was left to sort the problems out later on. So it would be better if I can get everything sorted to required standard from initial design onwards so to speak.

thanks

The new additions to the regulations are a good starting point, the best advise I could give is to follow your heart, and do what you think is right, so many times I have seen people being ripped off by bad installs, only to have to pay more later. I am in a fortunate position in that my advise is used by various organisations, and when any organisation finds out that it is me doing the design, they usually accept my advise.If you need any advise I will try to help if I can.

 

[steptoe]

Robin,

and Im not sure if I am speaking out of turn here,

but would it be prudent to perhaps employ the services of someone such as manator (or an equally conversant person) to act as a design consultant on something such as this?

:|

 

[Robin Spark]

Robin,and Im not sure if I am speaking out of turn here,

but would it be prudent to perhaps employ the services of someone such as manator (or an equally conversant person) to act as a design consultant on something such as this?

:|

Yes good idea, if its going to cost a bit more to get the work done right the first time then yep I am all for that. At least peace of mind knowing that everything has been covered to the various regulations will be covered.

Dont want to waste peoples time but maybe nearer to things materialising i'll pm Manator and see what we can organise.

 

[Manator]

No need really, if you have a copy of the new BGB, then look at the section for medical locations. You can only follow the guidlines they impose.

Me, Sidewinder and KME would probably argue this, simply because BS 7671 does not go as far as we would normally do during our everyday experiances. The most contentious point that I have is terminology, for years I have used the HTMO6 terminology, and now BS 7671 has decided to rename some instances and parts, which is just silly.

God help my next assesment, he is going to have to be made of strong stuff.

 

[Sidewinder]

I have already written to the NICEIC & the IET with regard to section 710 & some of the works that I do...

 

[Manator]

All I know is that I have bought more 10mm and 16mm earth cable, than I have ever bought before.

But what good results I get from my testing

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I need to learn how to apply a shocked face, not a Happy one. Whilst shocked, I could not say I am Happy as well!