Periodic inspection report help needed

[mattmoo1974]

Ze is external ie what teh DNO gives you, So it shouldnt be high TNCS 0.35 and so on.
I think you mean if your Zs is high, Then you look at the tabluated value for the MCB and may have to put in a smaller 1 or larger cble to bring your Zs value down.
Oh and MK i total agree with you on the college front. Testing sadly is over looked i feel, Needs to be one to one not a huge group exercise
Hope this helps mate. Oh buy yourself a GN3 but these are changing soon so either get 1 now or wait.
Think this book will explain a few things your asking here.

 

[malcolmsanford]

I think if you had posted your reply that you have, to my post first, then help would have been a lot more forth coming.

It sounded from your OP that you were carrying out a PIR as a job. I just thought it was prudent that someone pointed out that if it were a job, then the basic questions you are asking, belies the fact that you are not competant enough to be carrying out PIR's safely and/or interpret the results you get to give a formative assement on the installations condition.

I do now appreciate that your doing you own home, and that you are in the process of learning. I'm sorry if you felt my post was sarcastic, and if you had led with I'm doing a PIR on my home to learn ....................then as I mentioned I would have been more helpful.

There are quite a few people in our industry that are not as ethical as you, and decide to learn at the expense of the public, which IMO is selling our industry short as it tars everyone with that same brush of being incompetant. As like me the forum will know that your learning and I'm sure will be of a great help to you.

 

[mkoffulham]

ok so when doin a pir what would you code if service head was 10meters away from meter or meter was 10m away from fuse board and had no isolator to protect cable??

 

[mkoffulham]

also in commercial if the shop had no emergency lights or fire alarm systems what would you code that? do you have to code?

 

[nickblake]

First question is a code 4 2nd question there would be no code as its not a requirement in the regulations to install fire and emergency lighting in commercial premisis ,that would be down to the council and fire service , how ever under building regulations in domestic premisis it is that is for new builds , but if i was doing the PIR i would reccomend the installation of smoke detectors etc

 

[telectrix]

your 1st q. i would code 2 for that.2nd q. fire alarms and emergency lighting are outside the scope of bs7671 ( except for compliance with regs ) and so no mention should be made on a PIR where you are inspecting and testing the electrical installation.

 

[mkoffulham]

ok wel my meter is around 10 meters away in the outside box there is no space to fit isolator
what would you doo??

 

[malcolmsanford]

Try and fit one within 3 metres of where the meter is ................see regulation in section 434 and in particular regulation 434.2.1

What type of cable is the tails to your CU run in.

 

[mkoffulham]

It is 16mm tWin and earth from a 100amp isolator the fuseboard type but no fuse to protect would it be diffrent if it was swa,pyro,or double insulated tails
Also how do you work out dissconnection times??
Thanks for advise

 

[malcolmsanford]

Is that a seperate isolator?, if possible change it for a switch fuse, of 60amp, but if it's T+E buried then if your changing the characteristics of the distribution circuit you may need to fit an RCD for additional protection.

You will need to check the Zs of the circuit, There are a couple of ways you can do this either by calculation or measurement.

Honestly I think the more you are delving into this the more your unearthing things that, at the moment, is beyond you. Are you working or do you have mates that are sparks?

 

[mkoffulham]

i help the odd mate out sometimes on site as mate as i havent had all the experience i need.
so the dissconection times are the zs values you read .

 

[MKS]

I'd get a copy of GN3, honestly it will help you no end...