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[TJ (Tom) Cornish]

I'm not sure what to look for and I don't really have the equipment to test for all these things listed.
I always take my 3 prong tester and my non contact voltage tester with me to shows with shore power and I know what to do with my own generators but not sure if they will be any good to me on saturday.

Debbie, it's worth your time to own a basic digital voltmeter, especially when using a larger generator like this which can potentially be incorrectly configured.  Home Depot carries Klein multimeters, and this one for $50 would be a good starter:

http://www.homedepot.com/p/Klein-Tools-Auto-Ranging-Digital-Multi-Meter-MM400/206517333

A basic procedure for receptacle testing is below:

http://tjcornish.com/articles/power-and-electricity-artic/receptacle-testing.html

[Ivan Beaver]

Debbie, it's worth your time to own a basic digital voltmeter,

EVERY sound person should own and carry a simply volt/ohm meter.

There are SOOOOOO many cases where knowing how to measure simple AC and DC voltages (batteries for example), and resistance checks make life SO much easier and faster to troubleshoot.

At the current prices, there really is no excuse.

Heck even the $20 are MUCH better than nothing.

The key thing to remember is that with some, when the internal battery gets to low, they can give VERY wrong information.  Such as AC voltage reading 1/2 of what it should.  Batteries are cheap and last a long time-as long as you turn the meter off when not in use.  The better ones will shut themselves down after a period of time.

[Kemper Watson]

Ah, those pesky details....

Here's a run-down for Debbie and anyone else who's never had to check:

A) While the genset is not running:

1)  Using your Ohm meter, check resistance between any Earthing (ground) connection and the frame of the trailer.  It should be 0 Ohms or so.

2)  Using your Ohm meter, next check resistance between any Earthing connection and any Neutral connection.  It should be 0 Ohms.  This test tells you if the *generator* part of the assembly is bonded.  If so, all is good.  Connect the Earthing rod or electrode array to the "grounding" terminal in the lug bay if the rental shop has not done so already.  If there are more than a couple of Ohms between Earthing and Neutral (like it's OPEN), use a short (12" is plenty) piece of wire as a jumper between the Earthing and Neutral lugs in the lug bay.  Repeat measurement to verify bonding.

3)  Find the Voltage selection switch (usually inside the engine compartment) and make sure it's on either 120/240V single phase or 120/208V 3 phase.  Many gensets have a 480V selection and we *really don't want that*.  Do not change this while the engine is running.  While Don Williams indicates that the 50 Amp connections are fed separately, my experience is contrary.  It's a good thing for you peace of mind, anyway.  Close all doors & access panels.

4)  Gentlemen (and dude-ette), start your engine if there is not a technician or rental guy to do so.  Let the engine come to speed for a minute or 2, while doing so look to see if there is a switch for "Eco-Mode" or "Idle/full speed".  After that bit of warm up, switch to the full speed mode.

B)  Now that we're running:

1)  It's time to check the voltage, so turn on the breaker(s) and use Mr. Voltmeter to measure Hot/Neutral, Hot/Ground (repeat these for each hot leg), Neutral/Ground.  The genset may have switchable voltmeters but they aren't very accurate... You can adjust output voltage (usually a screwdriver adjustment on the control panel, but the newer microprocessor controlled gennies may have up/down buttons or other contrivances) if you find it too high or too low.  If you are unable to adjust to a nominal 120V, see A(3) and A(4) above.

(a)  You should find nominal 120V between each hot leg and neutral, each hot leg and ground, and ZERO Volts between neutral and ground.  If you find more than a couple millivolts there is a problem somewhere, as you have no attached loads at this point, right?  Hmmmm?   At any rate, you should see no voltage between these when metered right at the generator set.

2)  Turn off any circuit breakers you had on for testing, connect the feeder cable to the spider box and the other end of the feeder to the connector on the genset.  Switch the breaker back on and the repeat the voltage test on all the outlets on the spider box.  You may see a small bit of voltage between neutral and ground, typically 10mV - 50mV.  A little more doesn't indicate danger, but lack of maintenance...  You're ready to start plugging in!

The most likely problem you will have is that many/most rental shops do not send out an Earthing electrode or ground rod or the wire to connect it.  When discussing generators with clients who are arranging for the rental & delivery remind them you need those items for the "safety of the performers and to meet Electrical Code."  At one point we carried our own ground rods and wire until enough event rentals were inspected by the AHJ and customers were calling the 24/7 service phone number and the rental shops started provided them upon request.

Now the disclaimer:  The preceding description assumes the reader has sufficient knowledge, experience and education in electricity and other relevant topics to determine if the suggested tests, sequencing of tests and connections, etc is suitable to the circumstances and equipment present.  Reader assumes all personal and property risks and acknowledges that the prededing description is for illustration purposes only.  It is not meant to be a tutorial or to replace professional personnel.

Thanks Tim. I'm printing this out and laminating it to my trailer wall..

[Ray Aberle]

Yes - diesel - sorry. It's all gas to me 

Typically, a 45kW will have 26 gallons in the UNIT tank, and another 54 gallons in the TRAILER tank. (Nope, not converting to metric, sorry.) FTB (Full Tilt Boogie) an MQ will draw 2.6gph, so WORSE CASE (and you'd have to be hitting this hard!!!) you still have 10 hours of run time in the unit and another 20 hours in the trailer. Pop open the diesel compartment on the front- if you can see the diesel, you're gonna be fine. I did a festival with my 45kW; 9bx Kara per side, plus subs, wedges, stage power/backline, FOH and MON positions- and 13, 14 hour days was using BARELY a gallon per hour. I seem to remember 12-13ga each morning to refill from the previous day. (Raging levels of paranoia; I hate dropping into the trailer tank. If I can't see diesel I'm scared.)

-Ray

[Stephen Swaffer]

Heck even the $20 are MUCH better than nothing.

The key thing to remember is that with some, when the internal battery gets to low, they can give VERY wrong information.  Such as AC voltage reading 1/2 of what it should.  Batteries are cheap and last a long time-as long as you turn the meter off when not in use.  The better ones will shut themselves down after a period of time.

I would at least look for a Cat III safety rating-after all, you will be measuring mains power and if you are checking a 50 amp feeder there's quite a bit of energy available that you really don't want released accidentally.

If you ever plan to use it to verify the presence of power before touching something, your trusting your life with it.  A good Fluke (model 117 would be a great one) will last a lifetime-I found a used Fluke  almost new in box that was 20+ years old and worked perfect. that set me back a whole $15.  The Klein's offer a lot for the buck.

[Steve Ferreira]

You will need ESA to come and check the generator and connections as well, before firing it up.

[Kemper Watson]

EVERY sound person should own and carry a simply volt/ohm meter.

There are SOOOOOO many cases where knowing how to measure simple AC and DC voltages (batteries for example), and resistance checks make life SO much easier and faster to troubleshoot.

At the current prices, there really is no excuse.

Heck even the $20 are MUCH better than nothing.

The key thing to remember is that with some, when the internal battery gets to low, they can give VERY wrong information.  Such as AC voltage reading 1/2 of what it should.  Batteries are cheap and last a long time-as long as you turn the meter off when not in use.  The better ones will shut themselves down after a period of time.

Has the Mooshimeter caught on yet??

[Frank Koenig]

Has the Mooshimeter caught on yet??

I have a Mooshimeter, which I reviewed here a while back, and while it works fine as a low-cost data logger, I wouldn't trust anyone's life to it. Just too fiddly, with the app and all. Get a quality, normal electrician's meter. -F

[Rob Spence]

You will need ESA to come and check the generator and connections as well, before firing it up.

Assuming anyone involved in the event even knows what that is.


Sent from my iPad using Tapatalk Pro

[Ivan Beaver]

I have a Mooshimeter, which I reviewed here a while back, and while it works fine as a low-cost data logger, I wouldn't trust anyone's life to it. Just too fiddly, with the app and all. Get a quality, normal electrician's meter. -F

I have a mooshimeter as well.  It is a nice gadget.

The biggest issue I have is that it is really only good for power line voltages.

Mid to high freq are WAY off.

[ProSoundWeb Community]