how can u tell when the ballast is faulty in a light fitting?

Answer 1

put in a new bulb if it still isnt shining properly or it goes out fast change the ballast

Answer 2

A Ballast is a form of transformer, you should be able to check the supply voltage and get a similar output voltage if OK. Different ballasts will give various output voltages.
Ballasts are usually 4 terminal (2in 2 out) don't confuse with a choke (2 terminal) Signs of excess heat, browning is a typical fault.
The ballast is typically used inconjunction with a capacitor to increase the voltage to strike the lamp, then maintain the voltage and current once the lamp is lit. The capacitor can cause lamps not to strike up also so its worth checking this.

Answer 3

You need a voltmeter and you take the leads from the ballast and test them for the 120 volts or whatever it is there are various voltages that can be at the ballast. I f you don't have a voltmeter then you can try working tubes in another light and change them out for the ones in the light that is not working other than that there may be burn marks or leaking material that is a dead give away though try all that and see. I am a Certified Construction Electrician.

Answer 4

The way I always check, is to put in new bulbs/light tubes. If the new ones fail to light, the ballast is bad. You usually get a 'hint' they are starting to fail when they start to buzz really loud.

Answer 5

A bad ballast will buzz louder and louder, and overheat.
Look for black soot around the ballast, or see if it's leaking tranformer oil, which will look like tar dripping.

Answer 6

the easiest way to check is by putting in a new lamp (and starter if used), if it doesnt stike then theres a good chance the ballast is at fault (at my workplace we have found about 4% of new lamps are defective tho).