Minimum tests for a CU change

[Larnacaman]

A ''permanent'' Crimp connection, preferably with heat shrink insulation is always going to be a better solution than a Wago. What's more it even LOOKS more professional.

Can you imagine what a CU is going to look like using Wago's, if virtually all the incoming circuits ends need extending?? ....Do the job properly guys!!!

Oh, ....and a properly compression crimped cable (stranded or solid) in a correctly sized crimp ferrule and using a correctly sized compression crimping tool is going to be a far better connection than a Wago joint. Remember they are recognised as being the equivalent to a soldered joint in both conductivity and strength....

Let's not start over estimating the limits of these Wago connections. They are good, and have many legitimate uses, but they are not a substitute for all situations, and CU use, is i suggest one of them....

 

[m4tty]

I can see what your saying larnacaman but it's the same as the plumbers soldering copper pipes was the old way and plastic pushfit is the new way. Old school plumbers are never going to like the new age pushfit but it's being used widely now so no going back. Same as these wagos. Much quicker and easier but I still see where your coming from mate. Merry Xmas

 

[Larnacaman]

Thanks Matty, hope you had a good Xmas this year too.... :Y

I think that new and old ways have there place in industry m4tty, as far as plumbing goes i know what i'd rather have in my house, especially in the weather conditions your having now in UK No guarantee i know having copper, just that to my mind, bigger chance of those push fit fittings popping than copper splitting !! ...lol!!

They use that plastic push fit stuff everywhere here (Cyprus) these days, and have done for a number of years now. But when i had my house built, i stipulated that all internal pipework should be soldered copper and pressure tested to 2X the working pressure. (i have a pressurised system working at 4 bar) But all external pipework is of the plastic type....

NB... Seen too many of those push fit pipe fittings ''pop'' to have total confidence in them. Don't know if most were due to workmanship or not, just that i can't allow myself that confidence in them!! ..lol!!! :|

 

[batty]

Thanks Matty, hope you had a good Xmas this year too.... :Y I think that new and old ways have there place in industry m4tty, as far as plumbing goes i know what i'd rather have in my house, especially in the weather conditions your having now in UK No guarantee i know having copper, just that to my mind, bigger chance of those push fit fittings popping than copper splitting !! ...lol!!

They use that plastic push fit stuff everywhere here (Cyprus) these days, and have done for a number of years now. But when i had my house built, i stipulated that all internal pipework should be soldered copper and pressure tested to 2X the working pressure. (i have a pressurised system working at 4 bar) But all external pipework is of the plastic type....

NB... Seen too many of those push fit pipe fittings ''pop'' to have total confidence in them. Don't know if most were due to workmanship or not, just that i can't allow myself that confidence in them!! ..lol!!! :|

Now When I was training to be an electrician the people I worked for were heating engineers as well as electricians. Now I can assure you if pipe freezes when they defrost whether it be plastic with push fits or copper the pipe or fittings will be damaged We had a few jobs in the time I worked for them in unoucupied premises these were copper pipe installations and when they started defrosting they were a serious mess. I would think plastic would freeze at a lower temperature than copper but I am probably wrong about that. Now for somebody that does not actually work in the electrical contracting industry it is all well and good to have your opinions but have you ever actually used a wago connector? I personally think they are a better connection than crimps and will carry on using them be it in the neutral connection in switches that I do under floor in joint boxes and extending cables in consumer units if necessary. I know push fits can fail we had a bad one on a job in a club in London now this was a day job putting it right due to the position of it but that was because the idiot that did it had used a hacksaw to cut the copper pipe so the pipe was not square so would never have held. Any joint can fail be it copper brass or plastic its a fact of life.

 

[Larnacaman]

Batty,

As far as pipe types and connections go, it's all down to personal preference!! As i said above as far as i'm concerned, i haven't much confidence in them myself.... Therefore i would always go copper in preference to plastic...

Wago's..... Now think about how the push fit Wago connection works, your relying on a thin flat spring loaded copper strip holding on to the conductor. Now consider a compression crimped ferrule, that is squeezed and deformed into and around the conductor. You can pull and twist the cable as much as you like, all you would succeed in doing is snapping the conductor. Doing the same to a push fit Wago, is the way you are advised to release them!!! As i stated before, a correctly sized and crimped joint will always be a better electrical connection than a Wago push fit connector.

I haven't used a Wago connector, but have used other makes that work in exactly the same configuration. I like most here, think that these connectors are clearly the way to go as far as joint connections go. But there Not a substitute for every situation.

Who am i to tell you not to use Wagos wherever you wish to use them, that is totally down to you. What i'm saying is, they don't look right sitting in a CU, they look what they are. ...a Connector!!! At least a heat shrinkable insulated crimp looks and is, a far more professional job all round ....

 

[Adrian]

+1

 

[Apache]

I have conducted a little experiment to prove the superiority of the push-fits.

http://www.talk.electricianforum.co.uk/showthread.php?p=178178#post178178

 

[Ash]

I normally hide the wagos behind the DIN rail or somewhere where you can't see them, so tidiness is still there.

I used to think crimps were a bit flimsy but I didn't know you could get the ones you described, gonna check them out

 

[Larnacaman]

Ash,

They are available in insulated form, where that insulation is heat shrinkable. It makes for a sound and very tidy and professional finish/appearance....

Even in standard form you need to have decent crimping ferrules of the correct size for the cable. (The cheaper ferrules are indeed flimsy) You can then always apply your own insulating heat shrink covering...

 

[speedster]

Hi Reference the CU change.I am a registered electrician with NAPIT,and the normal procedure is to carry out a full periodic inspection before changing the CUnit.

You need to inspect the installation first. Whether you actually issue a PIR to the client is between you and him/her. Think about it.If you're fitting a new 17th edition unit (which I'm sure you will be) any insulation problems could well cause rcd trippling. There might be broken rings,disconnected earthing connections and much more.You shouldn't be connecting up an unsafe installation.Also you SHOULD be completing an Electrical Installation Cert. You need all the information from carrying out the PIR to complete your EIC. One more thing, the work is notifiable to the local authority.

Take care,you could end up with a very heavy fine or a jail term !!!!!

Best regards Speedster.

---------- AUTO MERGE Post added at 08:39 ---------- Previous post was at 08:34 ----------

Hi, Forgot to mention,obviously any faults found should be rectified before going any further.

Speedster.

 

[SPECIAL LOCATION]

Hi Reference the CU change.I am a registered electrician with NAPIT,and the normal procedure is to carry out a full periodic inspection before changing the CUnit.You need to inspect the installation first. Whether you actually issue a PIR to the client is between you and him/her. Think about it.If you're fitting a new 17th edition unit (which I'm sure you will be) any insulation problems could well cause rcd trippling. There might be broken rings,disconnected earthing connections and much more.You shouldn't be connecting up an unsafe installation.Also you SHOULD be completing an Electrical Installation Cert. You need all the information from carrying out the PIR to complete your EIC. One more thing, the work is notifiable to the local authority.

Take care,you could end up with a very heavy fine or a jail term !!!!!

Best regards Speedster.

---------- AUTO MERGE Post added at 08:39 ---------- Previous post was at 08:34 ----------

Hi, Forgot to mention,obviously any faults found should be rectified before going any further.

Speedster.

In an ideal world what you suggest would be all nice and hunky dory..

But this idealistic procedure has two key problems;

a) You will not get any jobs because you are quoting too high because you have to try and cover all bases & possibilities.

B) You will end up cutting corners and not doing a quality job because you realise half-way through the work that you are not going to make any money out of the job.

But as we live and work in the REAL world The reality is.... After consultation and discussion, we will do what the customer is willing to pay you to do. The idea that you can put right all anomalies you find on an installation is actually an unrealistic and unprofitable business model.

Also some of your arguments are misguided and actually contradict themseleves...

Think about it:-

An installation which by your definition is unsafe therefore you cannot put a new CU on... Is ALREADY in service, and probably has been for several years!!!!

So by your argument it is safer to leave an installation which has a few areas that require improvement with an older CU that can only detect overload..

rather than improve the same installation with a CU that can detect BOTH overload AND electric shock!? hmm fuzzy logic??

Generally it is more than a bit of poor insulation that causes RCD's to trip

There are numerous insulation problems that will NEVER trip an RCD.

Consider; for 30ma to flow (& trip RCD) we are looking at approx 7,666ohms or LESS continuity between earth & a 'L' or 'N'. This is considerably less than the 0.5Meg, (500,000ohms) Minimum acceptable. Again in the real world any single digit Megohm insulation readings would be requiring a bit of further investigation but will not be an immediate RCD problem. 9.0Meg thro to 1.0Meg are 900,000ohms and 100,000ohms which are ridiculously small leakage currents.. No RCD trips!

Most often there are dodgy appliances, borrowed neutrals etc.. causing RCD problems on CU changes.

Where rewiring of circuits is not practical, it is acceptable to reconnect circuits with no earthing.. Such as early lighting circuits wired in twin with no CPC. You make sure all accessories are class II and appropriate warning labels are fitted... etc..

It is quite possible to fill out an EIC without doing a PIR. and some electrical improvement work HAS to be done in stages because the customer has a limited budget.

These are a few illustrations of the difference between the text-book ideal world CU change.. and the reality of running a business, meeting customers requirements in the real world.

As always we should use these best scenario guidance notes etc..

but balance with a level headed, experienced, qualified judgment, with good dollop of practical common sense thrown in to evaluate on how to improve an installations safety within the customers budget.

:coffee

 

[speedster]

Hi, your points are all valid.But you do have to carry out SOME inspection and testing when carrying out a CU change. Personally I do not issue a PIR unless it is requested.Obviously any defects found which are not codes 1 or 2, can be rectified at a later date,and any defects found noted on the EIC.I mentioned the periodic report as the person who originally posted the topic seemed to be very much in the dark (not meant to be funny).He mentioned he'd worked for a company who's operatives checked NOTHING before changing a CU.Obviously he needs to know what checks SHOULD be done.And this was my point.to try to advise him not to just go ahead and change a CU,but do some inspection and testing.For instance the installation might not even be earthed.Also he will need quite a bit of information for the EIC,unless he makes it up !

Regards,

Speedster.