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Kohler 12 RES Neutral/Ground Connection

TNBob

Registered
Hi Guys,

I'm a newbie here and my Kohler question isn't about vintage equipment so apologies if this isn't an appropriate question. However, I lurked on the site a while and there seems to be a lot of expertise here so I'm hoping someone can help me out. First, some background.

I'm putting together a homestead far off grid and I recently installed a 6.5 KW solar array with a 17.5 KWH Li-Fe-Ph battery bank and associated equipment. It's working fine but as backup I'm adding a Kohler RES 12 propane fueled genny. My neutral/ground connection for the entire system is in the power center where the charge controllers, inverters, (and now generator input) all come together.

However, while installing the genny and reading the manual, I see that the neutral is bonded to the ground in the generator 'junction box' as well. Additionally there is a prominent decal indicating that the generator neutral is bonded to the frame.

There is also a statement in the Kohler installation manual that, "At installation, the neutral can be grounded at the generator set or lifted from the ground stud and isolated if the installation requires an ungrounded neutral connection at the generator."

Obviously, since I already have one neutral/ground bond in the system, I need to isolate this neutral and ground in the genny. All this is pretty clear and seemingly straight-forward.

Secondly there are additional instructions to connect the grounding cable (assuming they mean the equipment ground) to the generator set ground lug 'inside the controller compartment.)

There are no pictures are drawings to indicate exact locations in either case.

My problem is this - apart from the rather general directions, all of the wiring runs into a single box behind the control panel which I assume is both the 'controller compartment' and 'junction box' they're referring to. There doesn't seem to be any way to access the wiring in the box without practically dissembling the generator enclosure. I'll do that if I have to but it really seems strange to me that would be required. I tried taking the back off the controller compartment, but there just isn't room to remove it sufficiently to access the inside of the box,

I can sort of see where this level of effort might be required to swap the neutral/ground configuration because a lot of customers won't be doing that anyway. However, everyone will have to ground the genny and I don't see putting the grounding lug in an inaccessible location as a good design. Therefore, it has me scratching my head and thinking I must be missing something.

Bottom line is I have two questions:

1. Is there a 'grounding lug' in some location I'm overlooking (quite possible)

2. Is there some simple way to access the inside of this controller box that I'm overlooking as well. That's also quite possible, but from the looks of things, it all goes together a bit like a puzzle, with this side of the box bolted to one side of the enclosure with another side of the box bolted to another side of the enclosure. It looks like to me that if I take that all apart it's going to be a PITA and take three hands to get back together.

Obviously, none of this is a gigantic technical hurdle, but on the off chance someone is familiar with this set up and can clue me in to an easier way to get inside this box, I thought I'd post this question. Any help appreciated.

Many thanks,

TNBob
 

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Zephyr7

Registered
The wiring compartment may well be hard to get to. They build these things to be compact and ease of access in many cases is a secondary concern (if that), especially for things that won’t be accessed frequently.

The ground connection is probably in the same compartment as the phase and neutral connections. Ground is probably a copper lug bolted somewhere. I personally would use a compression lug on the ground wire and land it on a bolt or stud with a lockwasher.

I agree you should open the ground/neutral bond at the genset in your case. I’d also recommend running the power cabling to the generator in metal conduit (probably EMT) to ensure a little extra safety. Make sure control wiring is in a seperate conduit from the power conductors.

Bill
 

AlanR

Registered
You're in the right location - but they want you to take the end sheet metal off, too. Instructions for controller access start at page 36, page 37 fig 4-20 shows the controller compartment with the back off, and you can see what's probably the ground bolt/wiring visible on the floor of the compartment, behind the circuit breakers.

http://www.kohlerpower.com/onlinecatalog/pdf/tp6196.pdf

Alan
 

AlanR

Registered
Forgive me, it's been awhile, but I think these units had a connection box on the back.
They DO have a connection area in the back. Unfortunately, while they have separate connection points there for neutral and ground, that's NOT where they tied neutral TO ground - for whatever reason, they did it in the controller box. The neutral lead from the gen end (L0) goes along with L1 and L2 to the controller box. L1 and L2 go to the circuit breaker there, then to the rear connection area. L0 goes to a ground point in the box, then to the rear connection area. So, to isolate neutral from ground, you have to get into the controller box.
 

Birken Vogt

Email NOT Working
Picture #1. Two phillips head screws on the left side of the control box through the side cover. One bolt head into the floor down by the battery. Two bolts in the back. Remove all those, main generator side panel comes off, then remove the cover from the wiring box and all will be revealed.
 

TNBob

Registered
Thanks Bill,

Regarding:

I’d also recommend running the power cabling to the generator in metal conduit (probably EMT) to ensure a little extra safety. Make sure control wiring is in a separate conduit from the power conductors.
Already done. I separated the control and power wiring however I used metal flex as opposed to EMT as required by Kohler for vibration.

Thanks for your help and especially the quick reply.

Yep. This is pretty much what I thought but it seemed to be such an illogical and sucky design that I was hoping I was mistaken. Thanks for the confirmation.

Bill, Sorry I'm just getting the hang of this. That last sentence was actually meant to be in reply to one of Alan's posts. As you see I'm incompetent in many areas.

Thanks Alan,

That Service Manual will come in VERY handy. I had only the Installation and Operations Manuals. I appreciate the help.

Bob

Damn it! I did it again.

You're in the right location - but they want you to take the end sheet metal off, too. Instructions for controller access start at page 36, page 37 fig 4-20 shows the controller compartment with the back off, and you can see what's probably the ground bolt/wiring visible on the floor of the compartment, behind the circuit breakers.

http://www.kohlerpower.com/onlinecatalog/pdf/tp6196.pdf

Alan
Thanks Alan. That Service Manual will come in VERY handy. I only had the Installation and Operation Manuals.

Best, Bob

Okay, apologies to all for my message board incompetence. In attempting to give individual replies to each of your posts, they all seemed to get chained together in a single reply. However, I hope it was at least somewhat clear. Thanks to all for the help and sorry for the confusion.

It appears that rather than attempting to 'reply' to each individual post that I should just reply to the thread 'in general' and quote the post I'm to which I'm trying to reply.

Best - Bob

Okay, that didn't work either as my last reply was just tagged on to the bottom of my previous one. If anyone can clue me into what I'm doing wrong, I'd appreciate it.

Thanks,

Bob
 

Zephyr7

Registered
The forum merges all your replies into one lengthy post if no one posts something in between your multiple posts. Use “quote” and edit the quoted text and then it makes more sense since we can all see who you were responding to with each individual reply.

Don’t worry about it, we all started not knowing stuff and learn as we go :)

Bill
 

TNBob

Registered
Thanks to all. With a little info I was able to solve my problem and my Kohler genny now has the neutral isolated from the ground and the genny itself is well grounded.

I do have another question if anyone wants to jump in.

When I bought the genny, a carb heater was listed as an option and I bought it as an 'add on.' Not a bit deal technically as it just bolts on around the carb under the air cleaner and plugs into one of the 115 VAC plugs that are pre-installed on the back of the controller box. However, in looking at the installation manual the temp sensor is in the power cord and the thing comes on anytime ambient temp dips below 40 degrees F.

Okay in theory I suppose, but I'm totally off grid and solar powered and this thing using juice 24/7 when the temp hits 40 seems like a big waste of power. I figured it would cycle on at a MUCH lower temp, as we can go for days in my area with the temp in the 30 to 40 range. Even without the carb heater, the genny started first time every time during our recent cold spell with temps in the low 20s.

It doesn't use much power, but on the other hand, I'm sure there will be some point (especially as I 'add' stuff) when I'm counting every watt and I'm sorta beginning to think this impulse buy was a bit of overkill.

Any opinions from you folks familiar with Kohlers?
 

Zephyr7

Registered
The carb heater is just an aide, not totally required. It’s not like a block heater on a diesel that can be required to even get the unit to start at all.

Without the carb heater, in really cold weather, your unit might start a little rougher but you should be ok. You probably won’t notice much difference at all.

Bill
 
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