Basic Testing

[Floody]

Hi guys, brilliant new thred im sooooooo pleased this was set up I cant even begin to tell you.

Ok, Testing.

Im trying to find out the basic testing that needs to be done on all circuits. In college we are currently wiring lighting switches and ceiling roses. I can see the tutor lightly touching on it with other students but hasnt got round to showing me yet. If competant, I could grab a meter and test on my own (which is allowed).

If possible I would kind of like it in a list order that I can copy and paste onto a word document that I always keep round with me for reference. i.e

Test 1 - Checks for bla bla
Test 2 - checks for bla bla
Test 3 - Pee on this and see if your pregnant....oops..wrong test.


You get the picture.

Any help is much appreciated.

Once again, I love you Dan!

 

[Sparky Ninja]

Hiya Floody,

Are you looking for something specific with regards to the testing limited to the practice boards at college, for example:

Continuity of protective conductors
Continuity of ring final circuits - if applicable
Insulation resistance
Polarity

or

The whole thing that will be expected of you when you come to the assessments of Unit 2 of Level 3

 

[Floody]

Hi there, your first answer. Basicaly the basic checks, polarity, insulation reistance, continuity. A descriptive paragraph of each on what they check for. Put it in terms for a compete beginner if possible.

Thankyou Widdler

 

[Paul.M]

This is not mine so dont give me any likes or thanks for it, I've nicked it from Sintra's thread "Basic Testing Procedures" in the I&E forum so any thanks should be to him please.


2. Continuity of protective and bonding conductors


Reason: To check that all circuit protective conductors (green and yellow cables) are continuous and are present at every electrical accessory on the circuit. Also to check that the main earthing conductor and main bonding conductors are continuous and correctly connected.


Method 1: The line conductor is connected to the circuit protective conductor of the same circuit at the consumer unit and a measurement taken at ALL accesories on that circuit between line and c.p.c. The highest measurement obtained is recorded on the test report.
Test result is R1 + R2. The line conductor and neutral conductor are then connected and the above repeated to obtain R1 + Rn


Method 2 (used for main earth and main bonding conductors): A wandering lead is connected to one end of the conductor to be tested and a measurement taken between the other end of this lead and the other end of the conductor.
Test result is R2.
During this test polarity can be checked as well. The continuity of the neutral conductor can also be checked.


3. Continuity of ring final circuit conductors


Reason: This test ensures that all ring final circuits (sockets usually) are indeed a continuous ring with no interconnects or breaks within it.

Method: The line, neutral and earth conductors of the circuit are identified and a measurement from one end to the other end of each is taken. These results are r1, r2 and rn.
The incoming line conductor is then connected to the outgoing earth conductor and the outgoing line conductor is connected to the incoming earth conductor. A measurement is then taken at ALL socket outlets on the ring. The highest of which is recorded on the report.
This result is R1+R2 for that circuit. The above is then repeated using the neutral conductor instead of the earth conductor. This test provides R1+Rn which does not need to be recorded on the report but is essential to check the circuit correctly.


4. Insulation Resistance


Reason: This test checks whether the insulation around a cable is still intact and has not broken down over time. It is a good indicator of the age of an installation.

Method: An insulation resistance tester is connected across line and neutral of your circuit at the c/u. 500V DC are then pumped down the conductors to see if any voltage leaks across from one conductor to the other. The same is then done for the line and earth and the earth and neutral conductors.
(I've amended a little bit of this so it applies to the op's question, paul.m)

5. Polarity


Reason: To check that all accessories are correctly connected to line, neutral and earth and that all switches and circuit breakers are connected in the line conductor only.

Method: The method for this is the same as for continuity and is usually done at the same time by operating switches etc whilst conducting the test.


Read more: http://www.electriciansforums.net/i...1-basic-testing-procedures.html#ixzz28HF32fxV

 

[Floody]

Brilliant. Exactly what I was looking for.
What does he mean by R1 + R2 etc

 

[Sparky Ninja]

Brilliant. Exactly what I was looking for.
What does he mean by R1 + R2 etc

R1&R2 represents the value of the resistance of the line conductor (R1) and CPC (R2) combined.

They are identified at the furthest point (or points if it's a lighting circuit with joint boxes). You then connect line and CPC together at this point.

Then at the board test across line and CPC and the value obtained can confirm a few things:

1. That the CPC is continuous and not broken - This confirms the continuity of protective conductor test
2. That the switches have been confirmed to operate effectively - If you carry this test out at every light and you test to switch line and CPC, operation of the switch should result in the tester showing open and closed circuit - therein proving that the switch works.
3. Polarity - a combination of 1 and 2 above prove both correct connection at accessories and ensures that switching is carried out in the line conductor only, therefore polarity is confirmed for the circuit.



Further down the line you will also be able to calculate this value for comparison.

 

[Resu]

What we have just done at college is dead testing before energising the supply to our projects.

We do (and what you'll probably be doing first):
Continuity of CPC
Insulation Resistance
Polarity

As described above so no point in me going over it again.

 

[trev]

The only piece of advice I can add to this would be for you to buy a copy of guidance note 3, if you can't afford it just now borrow a copy from the college library. This book gives you chapter and verse on the testing procedures and will prove to be an invaluable investment for you.

 

[Baker1988]

Hi the tests we do at college is continuity of cpc/ r1 & r2 / insulation resistance of radial and ring / and polarity, they are all easy enough you just have to practice a few times me my self I bought a cheap UN calibrated robin tester for £65 off eBay then I got a board and accessorys and made my own circuits at home and practiced my testing in my own time also the guidence note 3 is a good book to have a look at I have it in a pdf if you want me to email you it pm me

 

[trev]

Practicing on a home made board is a good idea but it's very easy to slip into bad habits so as Baker said, get the book and get into the habit of doing it exactly the way it's described in there because, when you get assessed at college if you do it wrong you will fail

 

[Floody]

Thanks for all the info lads im making a 'testing' word document to jot all this down. Still a little confusing but I suppose things will become alot clearer once ive had a nose at a meter

 

[trev]

The diagrams in GN3 will help a lot too mate

 

[lee17th]

Been doing testing on all installations in level 2, but recently done the Inspection & Testing practical on a prepared installation with radial, ring, oven, etc, and found this to be the best way to finally really get it, everyone on the course felt the same. When you can spend time on it, it sinks in, and you actually understand why you're doing them.

 

[Floody]

Thats where id like to be at Lee
Its obvious that the more you do them, the more youll understand and it will become second nature.
Had a bit of an explanation from the tutor on Monday, so its sinking in a bit now.

 

[lee17th]

Got a couple of mind map things to help me remember,done them on some free app in Chrome, also a previous student did a pretty good pamphlet type thing which a lot of the guys on the course use, I'll dig it out and post it up if I can.