I have 115 v at the bulb receptacle but the bulb doesn't light up...whats the problem its a rab ff150 hps fixture

Nobody knows.

HPS bulbs and fixtures are normally designed to use bulbs specific to that fixture. Many times one type of bulb will work while a similar looking one will not. Make sure you use only the type specified on the fixture and you avoid the problem.

the outside of the receptacle has to have continuity to ground to complete the circuit.

Make sure both sides of the receptacle has 110 volts. Take meter and keep prong in ground slot and then put red prong in the others. You should have 110 volts in each one. If not change receptacle.

I have 6 of these in my lighting rig, and the most common problem has been a bad bulb socket. If your bulbs end up with corroded or blackened terminals, you should replace the socket. The black/corroded stuff can cause the connection to become intermittent, sometimes so badly it entirely doesn't work.

The other common problem I've seen involves a resistor on the circuit board that powers the light bulb. I believe it's R2 - regardless it's the only big one. It's value is .5 ohms at 3 watts. Be sure to use a flameproof resistor when replacing it, and most likely your fixture will light up again.

A ballast for a 1000 240 volt fixture will lose a small amount of output over time , but should nt be too noticeable . I suggest you take one of the dimmer bulbs and install it into the fixture that has the brightest bulb in it now . If the new bulb is now the brightest of all , then you know your other ballasts have lost some intensity . I have also seen on some bulbs depending on the gas inside the glass( ex. HPS or Metal Halide) which gives off the different color , will take a while on initial start up , to burn at full intensity . It is also possible that you were given used bulbs which would explain the 20 percent loss in intensity . Good luck

It doesn't sound like you are getting a true 230 volts to the timer. Measure from terminal 1 to terminal 3. You should read 230 volts. If you are getting 230 volts between 1 and 3, return the timer, it's defective. If you are not getting 230 between 1 and 3, then you'll have to have a look inside the electric panel to see what has been miswired. There should be a 2 pole breaker with a white and a black wire connected to it that goes out to the timer.

Hi .. it could be the ballast .. an easy thing to do to troubleshoot this would be to swap the lamps. If the problem follows the lamp. then that is the problem. If the pronblem stays with the fixture, then I would replace the ballast in that fixture.

if you are to do it right i would put the lights and receptacles on seperate 20 amp breakers and use #12awg wire it really depends on how much load you are to put on the receptacles and wether or not they will all be used at the same time. the lights will not draw much power at all but is always a good idea to seperate lighting loads from receptacles

The ballast may not be the problem. The problem may be the ignitor (starter). If the fixture humms, then the ballast is most likely working. Ballasts (transformers) do not go bad very often.