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Commercial EICR strategy?
AJ Spark
5 Posts
Question
Hi,

I've been tasked to do some EICR's on some commercial Car Showrooms. There's lots of old DB's, little or no circuit details and the previous EICR's stated that nothing could be tested due to not wanting circuits switched off. Personally I don't think it's worth even reporting if you aren't testing anything?

I wondered if anyone had a strategy for dealing with these situations. I'm not looking for anymore work so I'd rather not fail anything unless I absolutely have to. The customer wants as little interruption to the supply as possible.

A possible strategy:
Visual check
Identify circuits where possible
Take Zs readings where possible
Check db's for signs of thermal damage
Zsdb and ipf's
Check bonding
Check tightness of terminals in db's and sampled accessories
Report on what I've seen and tested with limitations on everything else.

It is going to be impossible to identify cpc's and neutrals associated with each circuit. IR testing would have to be very limited.

Below is a picture of what I am up against. There's a mix of old and new db's with many BS3871 MCB's.



Any advice guy's?
 
22 Replies
There's very little, to no reason why you cant switch off - in an environment like a car show room, to do the testing; what happens in a normal power cut?

The Server Rack should be UPS backed up. Sell them a UPS if not. Mondays in car show show rooms are normally very quite. 

If you have to only do live testing (Which does happen in some environments) a very helpful addition to what you have described above is a mA Earth leak detection on the tails - this will give a good indication of possible IR deficiencies - especially any N-E faults (Lots of Amps earth leakage). Further Investigations may be then be the outcome to the EICR.

Lots of long lead tests, Zs and Visuals is then your friend after that. 
kfh
161 Posts
Apart from the concerns you and Tatty have raised there are the issues around H&S. Wandering around with a stepladder and an R2 lead in an area with public access and staff wandering around as well, never mind IR testing at 500V.

If they cannot allow isolation both physical and electrical your process seems reasonable. 
Sparkingchip
4012 Posts
My experience of working in car main dealerships premises is that everything has been chopped about and messed with without any design considerations.

So a faulty coffee vending machine will take out all the IT equipment closing the business down, because they cannot even answer the phone never mind do a MOT, service or repair a car and sales are impossible.

The idea of doing inspections and testing in car dealerships is not appealing.
broadgage
610 Posts
And beware alterations that have been done not by a suitably qualified electrician, but by someone "who knows vehicle electrics, it is all the same, init" 
Warning signs include "Scotchlock" type connectors, and striped or odd coloured automotive wire.
broadgage
610 Posts
This sort of thing
Twin automotive wire
Sunday and evenings?
I was trained by a chap who after leaving Southern Elec went off to do bank jobs. They were all weekend and evenings only.
Legh
Zoomup
2724 Posts
Any advice guy's?

Walk, or if you do undertake this job allow many, many, days.

Z.
wallywombat
432 Posts
You could ask them why they've requested an EICR and/or what they want out of it. The answer to that would influence the testing strategy and scope. To comply with their insurance company's requirements? Or they want an idea of whether they need a major rewire/upgrade? Or random things keep tripping and taking out lots of other stuff and its getting annoying? Or they're just H&S conscious?
perspicacious
565 Posts
chap who after leaving Southern Elec went off to do bank jobs

Did he ever get caught Legh?

Regards

BAD
perspicacious
565 Posts
There's lots of old DB's, little or no circuit details and the previous EICR's stated that nothing could be tested due to not wanting circuits switched off.

I'd walk if that's their respect for the responsibility you're taking on.

Risk and reward...............

I do also wonder why the previous guy isn't doing it.

Two incoming meters?

Regards

BOD

 
perspicacious:
chap who after leaving Southern Elec went off to do bank jobs
Did he ever get caught Legh?
Regards
BAD


Of course not. In after dark and Out before the sun rose.
Left the place spick and span, no nails, screws, dust and wiring detritus on the carpets  Skirting boards replaced and newly painted left to dry in place. New sockets and switches ready to use but alas no wife.
After several years of making good money his wife ran off to enjoy evenings and weekends with somebody else.
Legh

John Peckham
688 Posts
Bod

Looks like 3 meters to me?
perspicacious
565 Posts
I've yet to learn how to enlarge the posted image John, but I thought the far left one was a single-phase check meter but it now looks as if its a separate incoming single-phase supply cut out under it.......

Did you like the sheared brass bolt image I sent you for your files?!

Regards

BED
AJ Spark
5 Posts
tattyinengland:

If you have to only do live testing (Which does happen in some environments) a very helpful addition to what you have described above is a mA Earth leak detection on the tails - this will give a good indication of possible IR deficiencies - especially any N-E faults (Lots of Amps earth leakage). Further Investigations may be then be the outcome to the EICR.
 
Afternoon tatty,

First time I've tried this but I've clamped the tails on various DB's.
On the Main DB that feeds 5 other DB's around the unit including the Comms room I'm getting around 50mA which peaks at around 75mA every so often. 
There's an Aircon DB which I get a pretty constant 40mA at.
There's a showroom lighting and general power DB which I get 20mA at.

How do those figures look? Would I be looking for readings of Amps rather than mA to indicate possible issues?

Cheers
AJ Spark
5 Posts
wallywombat:
You could ask them why they've requested an EICR and/or what they want out of it. The answer to that would influence the testing strategy and scope. To comply with their insurance company's requirements? Or they want an idea of whether they need a major rewire/upgrade? Or random things keep tripping and taking out lots of other stuff and its getting annoying? Or they're just H&S conscious?

Hi Wally, it's for insurance purposes. Anyone know what insurance companies are looking for?

perspicacious
565 Posts
Would a 30 mA RCD stay in at these values?

Regards

BOD
perspicacious
565 Posts
Anyone know what insurance companies are looking for?

Yes, to pass the risk onto you if you issue a satisfactory EICR, hence the need for PI insurance and your willingness to stand up in court to explain why you didn't record as unsatisfactory the item that you're up in court for!

As above, risk and reward.

Regards

BOD
AJ Spark
5 Posts
John Peckham:
Bod

Looks like 3 meters to me?

Hi John,

The main service head, 3 ph, feeds one meter (right hand lower) and the majority of the db's via henleys.
There's a PV import meter (above main meter). PV feeds into henley blocks.
Looks like the supply is looped to the left, single phase, to feed a economy 7 which feeds a redundant storage heater board and an Air Con board.

wallywombat
432 Posts
AJ Spark:

Hi Wally, it's for insurance purposes. Anyone know what insurance companies are looking for?

Fundamentally they're looking for a satisfactory report, so that they have less risk of paying out for the the building burning down or someone being electrocuted.
If that's the case, then the car showroom people will probably be very happy to agree in advance with you that many things can't be tested (e.g. no power downs due to customers on site / cars being serviced etc). The idea being that this will cause you to issue a satisfactory report - a report which is very clear on what the agreed limitations on inspection were.

AJ Spark
5 Posts
Hi BOD, looks like I'd have issues on the Aircon db but the rest would be OK if those 5 db's shared the leakage? I've not used this method before so I'm not sure what to expect in terms of leakage. What's your take on it? Cheers
mapj1
3413 Posts
There is no 'hard and fast' limit for what leakage is OK - it may be made higher if there are motors with inverter controls or lots of PCs with switch mode power supplies - normally it is the interference filters on electronic equipment that have some capacitance L-E (and N-E) that gives rise to the largest leakage component. Next after that are metal clad heating elements in cookers and kettles and so on.
As first stab at what is reasonable, expecting no more than a mA per amp or two of circuit rating  is a good start - so a 30mA RCD covering a 30A circuit might be leaking up to 10mA or so and not troubled. For a 100A sub-main, perhaps 30mA of leakage, and so a 100mA RCD if it was a TT supply.
However, the type of loads connected could affect this a lot - a single PC of the metal cased kind may add 3mA of leakage on its own, as may the electronics in an induction hob. Indeed sites wite many PCs (or many induction  hobs I suppose -  but less likely) benefit from being wired as a larger number of under loaded circuits - like small area rings and radials, so that the pre-load on any RCD is not too great, and the losses if it trips are minimised.
Mike.
 
AJJewsbury
2491 Posts
Check tightness of terminals in db's and sampled accessories
If the suggestion is to do that live, I'd be very wary. Insulated tools might be fine if all goes well, but it only needs an unexpected failure - like the heat of a screw shearing off - to put you in a very sticky situation (remove the screwdriver and the broken part might fall onto live busbars, but you can't sort it out without moving...)

I'd ask why they want an EICR - likely it's not just because they like collecting pretty sheets of paper - but do actually need to prove properly to someone else that their system is safe, and something full of ifs and buts and gaps and limitations won't really do. I suspect that in the end the answer will be to arrange an organized shutdown (likely out of hours) and do a proper job.

   - Andy.

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