Two questions on regarding Inspection & Testing. Please Help!

[nazoom]

Hi

I have two questions regarding inspection and testing:

1. What are the exact steps to carrying out Insulation resistance for three phase motor? Also where does the Red probe of the tester goes and where does the black probe of the tester goes?

2.What are the exact steps for carrying out RCD test? and where does the red and green probe goes? Also do we turn all the CBs and Main switches ON or only the CB under test is turned ON? And just to make sure do we connect all equipment and turn them ON during this test?

Any help much appreciated.

 

[electricians]

Hi Nazoom , to be honest , the fact you are asking this question , I think you should get someone to show you . Insulation resistance can easily cause damage to equipment and may be dangerous to occupants if not carried out correctly .

 

[Guest123]

http://www.electriciansforums.net/i...e-motor-please-help.html?highlight=motor+test

Whats wrong with answers you got here then???

 

[nazoom]

Hi thanx for the replies. The thing is I bought a book called Testing Electrical Installation by Anthony Hinsley MA MIEE and it is confusing me!! I am not sure when and in which test do we turn On the power to equipment like Circuit Breakers, Main Switches and RCDs. Also in which tests do we keep loads ON? So for:

1. Testing for Ze, Zs, RCD, individually what happens to the RCDs (do we turn them) ON or OFF?, All the Circuit Breakers ON or OFF?, and the Main Switch ON or OFF?. Also do we keep all loads connected/Disconnected?

Also in the same book for Insulation Resistance For 3 phase motor, it shows a picture of the Three phase Motor and there are 3 Shortening links in the DOL CONTACTOR 400V, 3 Shortening links in the Metal Clad Switches, and the Star/Delta links removed at the Motor itself!! Is this the correct steps or do we only disconnect the Star/Delta links at the motor itself and carry out the test?

I am sorry for this but I have to get the right answers!

I appreciate any help or answers to these questions.

Thanx a miilion.

 

[Guest123]

I would respectfully suggest you buy yourself a copy of GN3, because for you to not be sure of the safety precautions for the carrying out of testing procedures particularly Ze, you could be putting the safety of others at risk.

Also the links you mention at the contactor are probably just bridging the contactor out to complete the circuit from the CU to the motor.

 

[Marvo]

I agree with Electricians post, at best this is likely to cost you a perfectly good tester and at worst damage to the equipment you're testing or to yourself.

If the book is confusing you then the author is pitching his explanation at a reader with higher level of understanding of the basic principals. Use Google to get some more background on the fundamentals then go back to the book when you've filled in the blanks and it makes more sense.