Commissioning Procedures 2

[ShadyYehia]

Actually i'm newly envolved in a new project and i will be one of the Electrical Engineers that i'll participate in the pre-Commissioning & Commisioning Phase

AnyHow,I've some questions for all of u Engineers that could help me in this new step in my life

1- do i need to test low Voltage Circuit breakers or i've just to accept the certificate of the vendor attached with each breaker
and if i don't could u plz tell me the right test procedures ( i beleive that i'll need a primary current injector didn't i ? )

2- Enclosures of the Hazard Area Classification how can i test them or do i only accept the vendor certificates as they all will categrized as class 1 Div 2.

3- i'm sure that i've to test all the protection devise but i just want to ensure my procedures ?

All of u Engineers any one will answer me with a helpfull answers will really deserve a big star..................

Plz advice.

Regards,

 

[alehman]

The decision to commission various systems is normally up to the owner. There are certain types of facilities that may have government or regulatory requirments that dictate commissioning practices.

Commissioning and testing are two different things. This is a common point of confusion. The purpose of commissioning is to make a facility work as the owner intends. It can involve design review, installation verification, component and system testing, functional testing, documentation and training.

In general, low voltage circuit breakers should be tested in the field. I don't know of tests for hazardous location enclosures. One common source of testing specifications is the International Electrical Testing Association.

http://www.networld.org

 

[supraskate13]

I happen to commision alot of jobs and also do alot of testing. When commisioning "NEW" circuits you muct verify all wiring (again NeW wiring as existing wiring has already been verified) The best way to verify this new wiring is to ring out the circuits with a buzzer, and highlight the elementary as you go. Also perform functional checks...I.E. open a switch to see continuity go away and such.

As far as low voltage breaker testing. Fist of all make sure that they are not in service. Then you need to rack the breakers out completley to get them out of the shelfing. Once the breaker is out of its enclosure you need to crank it back into the racked in posistion (while the breager is drawn out of its casing). If there are arc chutes I recomend taking them off and cleaning them, you should scotch bright the contacts and also regrease the fingers out back that make up with the bussing. After the contacts are cleaned, I would ductor them. If the readings are good, put the arch chutes back on and then perform a megger test. ( CB open, across the contact. Closed phase to phase and phase to ground)

Usually low voltage breakers have test sets sold for that breaker. Some kind of ssecondary injection is usually performed to test the trip units. I would consult the manuals.

I hope some of this helps.

 

[supraskate13]

Oh I forgot to get into detail on the ductor and megger tests. A 10 amp ductor will work fine, close the breaker and measure across the fingers out back (top to bottom) remember that the bus in the back of the cubicle is most likley hot so maintain a clear distance. I like to pretend that there is an invisible plain to the entrance of the cubicle and while the breaker is drawn out I try not to cross the plane to much. As far as the megger, I use a 1KV hand held fluke, its quick, its portable, and its easy to use. the 1kv fluke is fine on 480V breakers, I take it this is what you are calling low voltage? if you get into medium voltage breakers I recomend going to a 5kv meggar. its always a safe bet to consult the manuals for ratings and consult the "Maintence" NETA testing book as it is more or less a bible for testing procedure