Do You.. CALCULATE or TAKE ACTUAL READINGS ??

[TPES]

I dont want go on about it too much as to what the positives and negatives are of calculating (or taking actual readings) when completing either a EIC, PIR or MWC...

Those of us who are testing on a very regualar basis will know the differences..

Im interested to know what method YOU choose to do when testing (the majority of the time)..?

I know in may depend on the perticular job and what money is in the job.. but im on about the majority of the time when your testing..

Please be honest..

(Your votes are not made public and other users will NOT be able to see what you have voted for)

 

[roukel01]

I'm sure there are alot of us on a Friday afternoon sat in our Vans filling out certs and '"Calculating" our results!!

 

[Davey101]

lol, I'd be surprised if many people on this forum admitted to anything a bit 'dodgy'.

 

[TPES]

lol, I'd be surprised if many people on this forum admitted to anything a bit 'dodgy'.

I was thinking this, and I'm sure many wouldn't want to admit it, in all honesty it would take a minimum of a day to test an average sized detached house if doing it properly, I was once told by 2 assessors that for them to test a property properly by the book it would take them at least 2 days, but to be honest there's hardly any customers that are going to pay you for spending the time doing this, it's not realistic for most of us trying to find work and make a living,

then the other extreme is going in and testing a full house is just over half hour....you may aswell not bother

it's a tough one, it's your name and address on the certificate and in a court of law you are held responsible for 6 years no matter what. So if your not testing properly your taking one hell of a risk if there was to be a fault or fire caused of a dodgy spur off the ring that you never picked up while testing...

 

[Johno]

table 9a OSG comes in handy, thats all i am saying

 

[Des 56]

I think a good measure of knowing you have tested enough may be

When you go home after testing an installation,know that what you have tested will be thorough enough to
allow you a good nights sleep if a fire occured killing the family who you had met the day before

It would be easier to come to terms with such an incident, if you do all to the best of your ability (whatever that may be) rather than have that ability and knowingly omit your responsibility

 

[TPES]

So how long is it taking you who are getting readings for example in a domestic house with 2 x Rfc, 2 x socket radials, shower, cooker, 3 x lighting, Heating, & alarm

if your doing your figure of 8 on the rings then R1 + R2 at every socket, ZS at every point, including every light fitting, removing all lamps to test switch feeds, dissconecting dimmers, transformers, neons and pir's. Long lead to test bonding,

how long on average is this taking you? Because to be doing this your either charge alot for CU change taking a couple of days, or spending the time doing this and not getting paid for it

and some of you say your doing All this prior to CU change!!!

 

[Gary D]

I was thinking this, and I'm sure many wouldn't want to admit it, in all honesty it would take a minimum of a day to test an average sized detached house if doing it properly, I was once told by 2 assessors that for them to test a property properly by the book it would take them at least 2 days, but to be honest there's hardly any customers that are going to pay you for spending the time doing this, it's not realistic for most of us trying to find work and make a living,

then the other extreme is going in and testing a full house is just over half hour....you may aswell not bother

it's a tough one, it's your name and address on the certificate and in a court of law you are held responsible for 6 years no matter what. So if your not testing properly your taking one hell of a risk if there was to be a fault or fire caused of a dodgy spur off the ring that you never picked up while testing...

Guys,

You must be doing it the long way if this is the case, I have an electrical company and amonsgt other projects we carry out test and inpspection in airports. In a night shift we aim for and achieve 40 circuits, completely tested with only a few limitations.

It's all about methodology & setting your stall out, if the methodology is incorrect you spend half your night hiking.

Also as owner of a training center Ican state quite catogorically that there is nothing wrong with calculation as long as you have taken Ze at the DB and you are measuring R1+R2, add them together - this is what makes Zs. A measured reading will always be lower due to parallel earth paths so calculation is worse case. If it meets BS7671 calculated then you are well in.

Calculation IS NOT guidance note 3 and a calculator!

And back to legwork...yes on the airports we calculate because we have just spent a few hours getting R1+R2s, we just add them onto the Ze, if it passes, hey ho, if not (but close) we go measure it and probably get a pass reading.

There are lots of time savers with testing without short cuts, in 2391 a delegate has to test 8 or so circuits in 2 hours (properly!) and record the results - not many more in a large domestic.

A newbie to us will do 10 - 15 circuits in a night if we send him out green, briefed to the methodology they constantly hit 40 circuits a night.

Anyone wants any advice contact me, and yes we do teach this methodology in our 2391.

Regards, Gary D
Home

 

[WayneL]

Not sure I see the point

The only one you can really calculate is Zs, which is pointless as, if you've had the fittings off to measure you R1 + R2, you might as well leave them like that and measure your Zs


As for the other tests:


Continuity of protective conductors..................no

R1 + R2.................................................not really, unless you know circuit length

Continuity of ring final circuit conductors............no

Insulation resistance...................................no

Polarity ..................................................no (although could be confirmed visually)

Ze ........................................................no (could enquire - probably be longer on the phone)

PFC........................................... yes (but whats the point if you're there measuring Ze anyway)

Zs............................................. yes (but you would need to have measured R1 + R2)

RCD/Functional .............................no

Volt drop.................................... yes


I honestly don't see the point in calculating anything (except volt drop), it's not saving you anything.

Insulation Resistance (done correctly eg 500v all tests) and ring final continuity are the two most time consuming - and these can't be calculated.

They can, of course, be guessed!!

 

[TPES]

WayneL... You can calculate R1+R2.. if not this can take up alot of time..

 

[Guest123]

WayneL... You can calculate R1+R2

As long as you dont use the formula R1+R2 = Zs-Ze, as unless you measure Zs with all the bonding conductors disconnected (not safe IMO) and any other obvious parallel paths, the reading wouldn't be a true reflection of the cable itself due to all the influences.

You would need to know the exact circuit length and allow for ambient temp to calculate it approximately.

Just not the done thing.....I'll stick my neck on the line and say R1+R2 should always be measured.

 

[TPES]

I'll stick my neck on the line and say R1+R2 should always be measured.

I Agree!

 

[Guest123]

I Agree!

........I know testing can be time consuming but along with a good design it's the most important aspect of the job. Just have to bite the bullet sometimes.

That said I'll also stick my neck on the line and disagree with the 2 assessors and say 2 days to test a standard 3 bed property is absolute nonsense.

 

[TPES]

That said I'll also stick my neck on the line and disagree with the 2 assessors and say 2 days to test a standard 3 bed property is absolute nonsense.

that's what I also thought, I assume they were trying to make a point on how important it is to do every test properly and that it should take anyone a certain amount of time to be done right

 

[pennywise]

I think I would be hitting 40 circuits a night in an airport! Nicely marked up boards, schematics and marked up accesories with DB designation on them. I think doing the equivilant amount of circuits in a large domestic property would be slightly different