Periodic Testing Percentage

[Chris Grant]

Hi guys just looking for a bit of advice. Just started a periodic test of a hotel, so far I have found the installation to be in quite good condition. What percentage of the installation do I have to test? I have read in guidance note 3 that you can do sample testing which is just a percentage, if i was to test say 20% of the installation which circuits do I choose to test and if I was just doing 20% do i do a full test on the 20% of installation and no test whatsoever on the remaining 80? Id carry out a full inspection of the installation.

 

[not clever]

Doing a percentage test of an installation for a pir, doesnt mean you do a percentage of the circuits but you do a percentage of the accessories on all circuits.

 

[zupos40]

Hi guys just looking for a bit of advice. Just started a periodic test of a hotel, so far I have found the installation to be in quite good condition. What percentage of the installation do I have to test? I have read in guidance note 3 that you can do sample testing which is just a percentage, if i was to test say 20% of the installation which circuits do I choose to test and if I was just doing 20% do i do a full test on the 20% of installation and no test whatsoever on the remaining 80? Id carry out a full inspection of the installation.

Why are you doing the test, when was the hotel last tested, since the last test, has there been any alteration or addition to any of the circuits.

Is this PIR part of a programme of planned maintenance.

Personnely if it 5 years or more since last test I would not be happy doing only 20% of circuits, the only time this would be acceptable if part of the hotel were inspected and tested yearly then with agreement of the responsible person/client to do 25 % minimum 20% new circuit and 5% of the circuit that were tested last year on the understanding that if any circuits fall either inspection or testing then the sample must be increased, this way the whole hotel will be tested within the 5 year.

If it more than 5 years then I be looking a doing a survey any near 80% inspection and earth continuity of all class 1 earthed circuits, insulation between Live- earth of all circuits, polarity of all sockets outlets, Zs of all sockets, testing of all RCD etc, inspection of about 10% of socket outlet.

Lighting thorugh inspection, continuity, live- earth and random Zs.

I inspect all CCU/ distribution boards, and all circuit in kitchens, laundry, plant room and other high risk area.

If you have limited experience also treat the test as a learning exercise, for future similiar work.

 

[peteludman]

i think that do 20% of the testing random amount of sockets and lights need to be checked when you do this.

if you find a lot of faults then inspect and test more.

have you past 2391?

you have it is down to you because you sign at the end of the day and its up to you how much you test really above 20%

i done 1 building with 36 34way dbs and tested 6 circuits on each db which is for the next 5 years
another had not been tested for 13 years and there had been a lot of jokers putting in additions so i done the whole lot and charged them for it to.

but you passed the 2391 so it is your call

 

[Mark.W]

i think that do 20% of the testing random amount of sockets and lights need to be checked when you do this.

if you find a lot of faults then inspect and test more.

have you past 2391?

you have it is down to you because you sign at the end of the day and its up to you how much you test really above 20%

i done 1 building with 36 34way dbs and tested 6 circuits on each db which is for the next 5 years
another had not been tested for 13 years and there had been a lot of jokers putting in additions so i done the whole lot and charged them for it to.

but you passed the 2391 so it is your call

As I understand it you don't test 20% of the board but 20% of the accessories in each circuit! You still have to test every circuit!

We're doing a periodic on an art gallery in london and there are around 47 boards, the installation was last tested 5 years ago and we are testing every circuit in every board, but only checking about 20% of the accessories of each circuit. ie if it's a ring with 10 sockets then we check 2 of them!

 

[andyb]

To justify only testing 20%, you will need the previous test results to compare results against.
If there is no previous results or they are too old you will have to fully test every circuit.

 

[peteludman]

To justify only testing 20%, you will need the previous test results to compare results against.
If there is no previous results or they are too old you will have to fully test every circuit.

YES sorry i should have mentioned the previous results are important to compare your results to if all is about the same then you make the decision how much u want to test over 20%

its realy your call

 

[tigerpaul]

How old is the installation? And what sort of standard is it at 1st impression? Do you have access to old schedules, test results , as fitted drawings etc?

I'd say if its over 5 years old I'd be pressing for a full test. That means you test every circuit, but you dont open every switch and socket.

If you test say 20%, then I'd test 1 in 5 cirucits fully, but I'd still inspect various accessories on the other 4 in 5 circuits, and if I found anything untoward, then I'd say the testing will need to be increased.

 

[Chris Grant]

Some parts of the hotel are newish around 3-4 years old and they have new dbs, but the older parts of the hotel are quite old with old dbs with numerous additions, acording to the hotel there are no previous test results or no circuit charts for the old part of the hotel. I have started in the old part of the hotel and came across a lot of problems already, most old 2D lights are all burnt out inside,connectors melting etc. sockets overloaded with kitchen equipment plus a lot of emergency lights wired incorectly,its like an oddjob guy has been installing a lot of additions, so have decided to do a full test on these parts of building. Iv also to test the leisure centre,gym and swimming pool and 2 restaurant areas and bars plus the new part with 60 en suite rooms at the hotel, not even looked at these areas yet but im hoping there is circuit charts for them as my boss is wanting the whole installation tested within 4 weeks !

 

[zupos40]

Some parts of the hotel are newish around 3-4 years old and they have new dbs, but the older parts of the hotel are quite old with old dbs with numerous additions, acording to the hotel there are no previous test results or no circuit charts for the old part of the hotel. I have started in the old part of the hotel and came across a lot of problems already, most old 2D lights are all burnt out inside,connectors melting etc. sockets overloaded with kitchen equipment plus a lot of emergency lights wired incorectly,its like an oddjob guy has been installing a lot of additions, so have decided to do a full test on these parts of building. Iv also to test the leisure centre,gym and swimming pool and 2 restaurant areas and bars plus the new part with 60 en suite rooms at the hotel, not even looked at these areas yet but im hoping there is circuit charts for them as my boss is wanting the whole installation tested within 4 weeks !

Best of luck, i can understand if you have test sheet and drawing, board charts, then sample testing if ok, but old part sound a nightmare.

Please let us know how you get on, finger crossed for you, personelly this type of job is a great learning experience.

 

[tigerpaul]

You can't rush testing. Tell your boss it takes as long as it takes..

 

[NoSparks]

On our course it was stated that it was 100% of circuits, 20% of accessories on each circuit. I would do an EFL test on every socket incase there were contact problems (I have often found 1 socket giving 7,8,9 ohms ) How would you feel if a week after you did your test there was an electrical fire? - its happened where a socket overheated and caused a fire!

 

[zupos40]

On our course it was stated that it was 100% of circuits, 20% of accessories on each circuit. I would do an EFL test on every socket incase there were contact problems (I have often found 1 socket giving 7,8,9 ohms ) How would you feel if a week after you did your test there was an electrical fire? - its happened where a socket overheated and caused a fire!

Yes 100% test for new installation, but periodic are slightly different, Inspect all the sockets for damage, I prove continuity using the R2 method, then prove conductor form a ring if circuit ring final, only if result are not satisfactary will I perform full ring continuity, then insulation test between Live-Earth then live and neutral on 250V, if ok the 500V, if circuit has neon in etc do not do Live to Neutral, then make live and use martindale or ELZ tester to prove polarity, Yes ZS every socket, also check switch working at the same time, Yes test every RCD.

Lighting R2 method, insulation between LIVE and earth only if all the lights were working before I did the test, also if dimmer in place, (alway test dimmer working on inspection before starting any test, (you be amazed how many faulty dimmer i have come across)

Domestic installation I ElZ furthest point only, commerical I may do more than 1.

Finall all CCU distribution boards are inspected Ze Zdb etc plus Ipfe and I pscc are measured

I never do as must inspection or testing on periodic as that are required for new installation, I do end up doing a lot of faultfinding etc

As I stated in previous blogs, I worked on preventive maintenance programme where an installation was tested over 5 year period testing only 25% of the circuits each year, 5% of the pervious year and 20% new circuits, so it is possible that you could be testing only 20% of and installation each year.

 

[NoSparks]

tested over 5 year period testing only 25% of the circuits each year

5% each year represents 100% every 5yrs which seems to agree with everybody else, except that the inspection is spread over 5 smaller inspections - so I hope your making a good profit on it!

 

[zupos40]

5% each year represents 100% every 5yrs which seems to agree with everybody else, except that the inspection is spread over 5 smaller inspections - so I hope your making a good profit on it!

I did at the time Keep me very busy inspecting ang testing earned over 35K each year for about 4 years, that how they wanted me to do them, it was government contract, testing historic buildings, even tested part of the tower of London, St James Palace, etc. Great times, good experience, great people to work for, I miss them.

 

[Cygnet]

This is my first post on the forum so here goes! ..............................................................As it has already been said initial verification on new installations is 100% of every circuit. Periodic test and inspection is different in that it is more inspection than test. The testing scope can be influenced by the client operations and you need to get this agreed with them before you start under the limitations. You may have a situation where the client has a comms / Data room which cannot be switched off, so they may require a visual non-intrusive inspection and no testing. Flag this up on your certification. You may also have, on the day access issues to rooms etc, note these down as well under operational limitations. In most cases its what you havent done as opposed to what you have done that needs to be highlighted to the client on the paperwork. Buildings with test records I would aim to carry out a test on 20% of the final circuits, and compare readings if you find anomallies do a further 20%. I would also carry out an Insulation resistance of the whole DB Neutral to earth as a N-E fault is the most common to go undetected, you wont flag it up by doing a ELI test or even the plug in 'Martindale' tester. If you are unsure as to end user electronic equipment initially carry this out at a reduced voltage of 250V dc. Periodic testing you don't follow the same testing sequence.

If there are no test records, you need to tell the client from the outset that a full 100% test is recommended, again thay may not want you to do it, operation / cost etc so get it written down in your limitations. If they dont want it and are not going to pay for it then dont do it just cover your self on the documentation.