Testing Times!

[richardg]

Good evening gentlemen, some much needed advice is sought. I have spent the last 9 months exploring the finer arts of domestic EICR. This is as you can imagine - a steep learning curve. Whilst I feel reasonably confident in the domestic sector the sniff of my first commercial EICR sends panicky signals to my grey stuff!
My family have asked me to perform a EICR on a mid-sized supermarket and Postoffice. This has left me scratching my head wondering how to proceed.


THE INSTALLATION
4 x 3 Phase DB
1 x Main Post Office
Shed loads of circuits 100+


Unfortunately there are no previous records. A majority of the circuits have to remain energised.


What in your opinion is the best way to proceed?


Prospective Plan


Perform a though visual inspection
Catalogue each circuit on test sheet
Record Ze,PSCC , PEFC ,main bonding ect
Record R2 of each circuit
Test Zs of each circuit


In the commercial sector what is the norm when testing? Especially when circuits have to remain energised.


All replies welcome, it all helps in the continual training you gentlemen help provided.


Regards


Rich

 

[telectrix]

first, to measure Ze, you need to isolate the installation and disconnect the earth. so it's a non-starter straight away, unless you do some of the work out of hours. second, if you are not completely comfortable with 3 phase, get someone who is to assist and share the take.

 

[Jay Sparks]

All installations are different so there isnt really a norm. You need to agree the extent and limitations with the customer. Any tests you cant perform (because they need to stay energised), you put a LIM on the cert. Test what you can.

 

[Jay Sparks]

first, to measure Ze, you need to isolate the installation and disconnect the earth. so it's a non-starter straight away, unless you do some of the work out of hours. second, if you are not completely comfortable with 3 phase, get someone who is to assist and share the take.

He could ring DNO for this but that would be a long wait and waste of time..lol

 

[zupos40]

What circuits have to remain energised. The reason for performing EICR is to ensure the installation is Safe for use. when I inspected and tested this type of installation I done the work out of hours, supplied temporary lighting and power via small generator, I do the inspection before hand and return perform test during the night time. I know a lot of people now do not test all the circuit and write on test sheet limitation, But please remember why you are there, I worry that the circuit I did not test could be the circuits that are faulty.

 

[richardg]

3 of the DB can be isolated, its just the Postoffice who insist on a unbroken supply. (Computers linked to main system) the testing will be started after hours 9PM. The three phase isn't too scary, though I might ask a more experienced professional to assist...

 

[zupos40]

3 of the DB can be isolated, its just the Post office who insist on a unbroken supply. (Computers linked to main system) the testing will be started after hours 9PM. The three phase isn't too scary, though I might ask a more experienced professional to assist...

Yes probably power for time lock safe, I done betting shops / building society etc and they arranged for the computer to be taken off line while I tested the installation, they then re connected to network ready for business the next day. I ask post office manager.

The rest of the shop you can test ok.

 

[richardg]

Sounds like a plan - will discuss with the manager ASAP. Your right a time lock safe a lots of computers

 

[zupos40]

Main thing to remember with 3 phase is to preform earth Ze on each line to earth and both Ipefc (prospective Earth fault current) and Ipsc (prospective short circuit current) on each line separately, then double the highest IPSC measured.

 

[zupos40]

Do you have access to IR thermometer and torque screw driver. A thermometer would help you to check for loose connection in a live board as it will show up as an increased temperature, the torque screwdriver to correctly tighten all terminals.

 

[zupos40]

Do you have access to IR thermometer and torque screw driver. A thermometer would help you to check for loose connection in a live board as it will show up as an increased temperature, the torque screwdriver to correctly tighten all terminals.

Electrical Applications for Infrared Thermometers | TechwareLabs

 

[richardg]

Electrical Applications for Infrared Thermometers | TechwareLabs

I'm sure a mate of mine has an IR reader in his black box van. Ill ask him to rummage around, otherwise I can rent one from my local store. From your link it seems an IR reader can be useful in commercial EICR. Thanks

 

[oldtimer]

Yep good shout telectrix about 3 phase if you are not sure then get advise domestics are ok but 3 phase is a different ball game ie measuring across the phases

 

[Clive P]

Hi,

What happens when the Post Office has a Power cut?
Do they have a UPS covering their Computer terminal?

Regards.

 

[Clive P]

Hi,
If they haven't , you could offer to fit one.

Regards.

 

[Marvo]

its just the Postoffice who insist on a unbroken supply

Lol, if I had a pound for every time I was told 'we can't knock the power off' I'd have retired years ago. Speak to the manager and remind him of his legal responsibilities to ensure safety of employees and the general public and tell him there will be a requirement for an arranged power down so he must just stop moaning and start making the necessary arrangements. You can also remind him that the testing will highlight most issues that could cause future power outages and instabilities so not allowing the power-down for full testing is actually shooting himself in the foot in the long run.

 

[Sharpend]

Well said, it always amazes me that electricity is the unseen enemy, yet so many businesses think you have magical powers to fault find/test without powering down. It begs the question what kind of service have they been used too by previous electricians. Why can't we just do our job and do it correctly?

 

[Marvo]

I think a lot of the time they just take a chance because it's a lot of hassle to power down machinery and POS systems and computer servers etc. Possibly the tactic has paid off in the past where other electricians have compromised. If they're adamant they won't allow the power outage I warn them I'll insist on a copy of their in-house regulations that prevent it and the refusal in writing with their signature on it so future issues will be referred straight back to them with proof.