MEP003a electrical questions

[noflyguy]

I have the MEO003a unit in my shop and the ground rod for the unit is not available from within my shop. Do I need to have the unit grounded while starting up to test and warm up? If so, can I use the ground bar in my shop electric panel to ground the unit at the same time as I use the panel to put a load on the unit? Also, how long can you safely run the unit without putting a load on it? Thanks for any help.

 

[Scoobyshep]

I have the MEO003a unit in my shop and the ground rod for the unit is not available from within my shop. Do I need to have the unit grounded while starting up to test and warm up? If so, can I use the ground bar in my shop electric panel to ground the unit at the same time as I use the panel to put a load on the unit? Also, how long can you safely run the unit without putting a load on it? Thanks for any help.

I would argue that utilizing your shops electrical service ground is far better than an independent ground rod.

Unless you have the head disconnected in a manner that will prevent it from creating power you absolutely should have it grounded while running as it is still capable of producing electricity.

Now in reality how many times do people actually ground a generator when they're just running it? Less than you would think, however this method you have to be lucky every time it just takes one fault to completely ruin your day and potentially the rest of your life.

The risks you face of running this generator without a load is mainly wet stacking. It takes hundreds of hours to build up Gunk from incomplete burn, even then all you really have to do is get it hot to burn the junk out of it once in awhile

 

[Chainbreaker]

Regarding your potential "Wet Stacking" question... I typically limit a no-load test to ~15 minutes or less depending on what I'm doing... like just exercising/testing: the fuel pumps, INJ Pump, Injectors, circulating oil and verifying there is AC output & all gauges are operational and no fuel or oil leaks anywhere.

Anything longer, I like to put a load on the genset for 30+ minutes running with a 5kw shop heater for my -002a and 10kw shop heater for -003a to really test output and get oil hot and cylinders/heads up to typical loaded temps to prevent wet stacking & flush out any "under load issues" that may have crept up before I'm running under "mission critical situations" such as power outages in dead of winter or outages during heat of summer.

I always like to run with genset fully grounded, but I must confess I have run some short start up tests with my gensets on their trailers with the only ground being the metal landing leg of trailer tongue touching earth. Edit: I forgot to mention I am always standing on a remnant of a 3/4" thick horse stall mat (high density rubber) even when genset is properly grounded, when I'm at the Control Panel starting/stopping generator(s). I just feel safer especially when ground is wet and I'm touching genset when I'm standing on thick rubber.

I installed heavy duty switches on my gensets that allow me to run as either aa a "Self-Derived System" with driven ground rod (remote field running mode) and did the mod configuration with the gnd cable detached from genset frame in order to utilize house ground through the cable going to house breaker box. I'm no electrician but as I understood it, it's necessary to modify the typical field ground setup and to prevent inducing a potential ground loop situation when powering house during outages. Though I have run across some comments to the contrary.

 

[Scoobyshep]

Regarding your potential "Wet Stacking" question... I typically limit a no-load test to ~15 minutes or less depending on what I'm doing... like just exercising/testing: the fuel pumps, INJ Pump, Injectors, circulating oil and verifying there is AC output & all gauges are operational and no fuel or oil leaks anywhere.

Anything longer, I like to put a load on the genset for 30+ minutes running with a 5kw shop heater for my -002a and 10kw shop heater for -003a to really test output and get oil hot and cylinders/heads up to typical loaded temps to prevent wet stacking & flush out any "under load issues" that may have crept up before I'm running under "mission critical situations" such as power outages in dead of winter or outages during heat of summer.

I always like to run with genset fully grounded, but I must confess I have run some short start up tests with my gensets on their trailers with the only ground being the metal landing leg of trailer tongue touching earth.

I installed heavy duty switches on my gensets that allow me to run as either aa a "Self-Derived System" with driven ground rod (remote field running mode) and did the mod configuration with the gnd cable detached from genset frame in order to utilize house ground through the cable going to house breaker box. I'm no electrician but as I understood it, it's necessary to modify the typical field ground setup and to prevent inducing a potential ground loop situation when powering house during outages. Though I have run across some comments to the contrary.

Separately derived is what is in the NEC, little nitpicky but for the benefit of the next person trying to Google it it's best to use the term in the book.

There is a lot of contention over grounding as there are way too many rules and exceptions to cover. In trade school, grounding took up almost an entire year, so it's confusion is understandable.

The short and dirty version is of you drive a separate rod at the generator and it's permanently attached to your service ground, that conductor is now part of the grounding field and should be appropriately sized for the service size. So for a 200A service, 4 awg minimum. No one in their right mind wants to run 3 10 awg feeds and a 4 ground (unless you just love pissing money away on copper).

Please keep in mind that the landing gear isn't sufficient for a proper ground. In some cases, the ground rod(s) aren't a proper ground. Odds are it will never cause you harm, BUT it only has to go bad once to ruin your day.


Hope this makes sense, if anyone wants to talk more grounding and bonding feel free to ask,

 

[noflyguy]

Thanks guys for the info. Looks like ground thru panel and to fully test, put a load on the unit. I appreciate the dialog.