If you Google “Stan Honey marine grounding systems” you’ll find links to a couple of versions of a well developed paper on grounding. I’m not an expert but as a EE I didn’t find anything in it that I disagreed with. I consider it basically definitive at this point.
Just FYI On Sat, May 30, 2020 at 7:42 AM bwhitmore via CnC-List < cnc-list@cnc-list.com> wrote: > Hello all, > > Josh, or Edd, this might be a perfect question for you folks. Where is > the star ground and the shunt located on our C&C 37/40+ boats? > > This is a perfect discussion, as I was having grounding issues of my own > and the shunt and star ground cannot be found behind the circuit breaker > panel, nor are they at the batteries, and I don't think I've seen them in > the engine compartment... > > Thanks! > > Bruce Whitmore > 1994 C&C37/40+ > "Astralis" > > > > Sent from Samsung tablet. > > > -------- Original message -------- > From: Dave S via CnC-List <cnc-list@cnc-list.com> > Date: 5/30/20 10:33 AM (GMT-05:00) > To: Neil Andersen <neil.eric.ander...@gmail.com> > Cc: Dave S <syerd...@gmail.com>, cnc-list@cnc-list.com > Subject: Re: Stus-List Grounding > > Feels like a leading (but good) question, lol - and I’d expect the > ‘grounds’ could be at different potentials and that this delta would vary > based on the ground at different marinas. > You’ve made me curious, will measure the ground-to-ground voltage today. > Not sure of the practical negative (if any) implications of the AC ground > being at a slightly different potential than the isolated -12vdc ‘ground’? > I can see that a poor -12vdc ‘ground’ could impact noise suppression in > cable shielding or similar but otherwise Is there an issue? I’m Not a > grounding/bonding expert by any means! > Dave > > > On Sat, May 30, 2020 at 9:56 AM Neil Andersen < > neil.eric.ander...@gmail.com> wrote: > >> Does that set up a different ground potential when connected to shore >> power (AC side and 12V side)? >> >> Neil Andersen >> Rock Hall, MD 21661 >> ------------------------------ >> *From:* Dave S <syerd...@gmail.com> >> *Sent:* Saturday, May 30, 2020 9:41:36 AM >> *To:* Neil Andersen <neil.eric.ander...@gmail.com> >> *Cc:* Brian Davis <brianwdavis...@gmail.com>; cnc-list@cnc-list.com < >> cnc-list@cnc-list.com> >> *Subject:* Re: Stus-List Grounding >> >> Interesting question. The term ‘ground’ probably should be distinguished >> from the negative side of the dc circuit. >> Can’t speak to more sophisticated boats but in my relatively simple 33-2 >> The AC system is isolated, grounded only when connected to shore power. I >> do not run any AC loads otherwise, no inverter. >> The 12v system would ultimately ‘ground’ To the water via the engine, >> prop and shaft. >> >> Dave >> >> On Sat, May 30, 2020 at 9:33 AM Neil Andersen < >> neil.eric.ander...@gmail.com> wrote: >> >> Where do you actually go to “ground” off the bus?? >> >> Neil Andersen >> 1982 C&C 32 >> Rock Hall, MD >> ------------------------------ >> *From:* CnC-List <cnc-list-boun...@cnc-list.com> on behalf of Dave S via >> CnC-List <cnc-list@cnc-list.com> >> *Sent:* Saturday, May 30, 2020 9:18:24 AM >> *To:* Brian Davis <brianwdavis...@gmail.com>; C&c Stus List < >> cnc-list@cnc-list.com> >> *Cc:* Dave S <syerd...@gmail.com> >> *Subject:* Re: Stus-List Grounding >> >> Essentially yes, however when you are thinking of the boat's wiring, I >> would think of the ground bus as the centre, with the engine connected to >> it, rather than the reverse. Think of it a hub or a star - with the >> ground bus at the centre. (Google "star grounding") one of those paths >> has to finally cross the shunt to be measured. (those loads which are >> powered by the house bank) >> >> That green wire is the ground for the aluminum fuel tank. The rest are >> batteries (house 1,2, and start) or engine, plus the shunt. All are at >> the same ground potential. On the other side of the shunt is >> the smartcharger, the refrigeration unit, the house breaker panel, and >> anything else I want to "see" in the BMV 700. Basically anything that >> impacts the house bank, (though this does not include the alternator.) >> >> Dave >> >> >> >> On Sat, 30 May 2020 at 08:43, Brian Davis <brianwdavis...@gmail.com> >> wrote: >> >> Thanks, Dave. I have the same type of shunt that came with the Blue Sea >> panels I'm installing and will have the same monitoring. I see in you pic >> there's a green wire (grounding?) going to the bus along with the blacks >> (negative batteries). So, all of that goes to the same engine connecting >> point and the grounds and negatives share that single point? Just want to >> make sure I completely "get it". >> >> Thanks for all your guys help. >> >> On Sat, May 30, 2020 at 8:21 AM Dave S <syerd...@gmail.com> wrote: >> >> Agree with Joe's comment. the engine must be grounded but should not >> be used as your primary grounding point. >> there are a buncha' good reasons for this. Another thing to consider is >> providing for an upgrade the battery/power monitoring, for which you may >> need to install a resistive shunt between the battery and the various >> grounds you wish to monitor, Here's a photo of the shunt (on the >> right) and ground bus (left) in my 33-2, you can see the ground bus and >> various grounds attached, this bus is connected to one side of the shunt, >> the other side of which is connected to the house breaker panel and the >> other accessories that are measured by my battery/power consumption >> monitor. This is the shunt that victron provides with the BMV-700. >> >> >> https://3.bp.blogspot.com/-LeNHHo5kK2k/V5V0MaFJ_cI/AAAAAAAAAkc/VI_Cm3z-Aa0m_dZ9AmlgaeVdXmXQOINkgCLcB/s1600/blog%2Bgrounding%2B2.jpg >> >> >> >> Dave >> >> >> >> >> >> >> >> -- Forwarded message ---------- >> From: Brian Davis <brianwdavis...@gmail.com> >> To: cnc-list@cnc-list.com >> Cc: >> Bcc: >> Date: Sat, 30 May 2020 07:32:16 -0400 >> Subject: Stus-List Grounding >> Hello everyone, >> >> Hope you quarantine projects are going well. >> >> I have a question about grounding. I'm currently refitting ALL wiring >> from scratch on our 1980 Landfall 38. I literally gutted every piece of >> wire and bought all new Ancor tinned marine cables in every guage you can >> imagine. She's coming along swimmingly, and I've mapped everything out >> pretty well in a 8 page layered diagram that I'm happy to email direct to >> anyone who wants it. It's in PowerPoint and about 8mg. >> >> My question about Grounding is if it's ok to use my engine as the >> grounding point? I'm using the similar area for the Negative connection for >> the 3 battery banks, but a different bolt to the engine case. Several >> appliances including the breaker panels, ACR, battery charger, water >> heater, fuel tank, etc require a ground and I'm using a 6 awg green wire >> from the engine to a large Blue Sea busbar. Then connected the grounds to >> it. >> >> I've also run a 2awg wire from the mast step to the keel bolt and to one >> of the stanchion bases from underneath for lightning protection. However I >> kept that all separated and not connected to the grounding. >> >> Make sense? Or am I missing something? Again, happy to send my diagram >> for review. >> >> Regards, >> Brian >> South FL >> >> >> >> ---------- Forwarded message ---------- >> From: Joe Della Barba <j...@dellabarba.com> >> To: cnc-list@cnc-list.com >> Cc: >> Bcc: >> Date: Sat, 30 May 2020 07:52:37 -0400 >> Subject: Re: Stus-List Grounding >> >> Don't use the engine for ship's ground. Use one of these: >> >> >> https://www.bluesea.com/products/2127/MaxiBus_250A_BusBar_-_Four_5_16in-18_Studs >> >> Your AC ground bus will connect to that ground point as well. Speaking of >> AC, make sure you have a galvanic isolator. >> >> Run ONE ground wire to the engine. You don't want your engine block to >> be a routine conductor of electricity. >> >> Here is your lightning ground conundrum: The old way was to connect all >> metal together. Coquina came with a ground wire system that connected every >> single thru-hull, the mast step, the engine and the keel. The problem with >> that is if the zinc does not work perfectly, you can have electrolysis on a >> large scale since you have all this metal wired together. I undid all that, >> no thru-hulls are wired to anything. The mast is wired to a keel bolt with >> 4 gauge wire. The ship's ground bus is wired to the engine with one ground >> wire. >> >> >> Joe Coquina >> On 5/30/2020 7:32 AM, Brian Davis via CnC-List wrote: >> >> Hello everyone, >> >> Hope you quarantine projects are going well. >> >> I have a question about grounding. I'm currently refitting ALL wiring >> from scratch on our 1980 Landfall 38. I literally gutted every piece of >> wire and bought all new Ancor tinned marine cables in every guage you can >> imagine. She's coming along swimmingly, and I've mapped everything out >> pretty well in a 8 page layered diagram that I'm happy to email direct to >> anyone who wants it. It's in PowerPoint and about 8mg. >> >> My question about Grounding is if it's ok to use my engine as the >> grounding point? I'm using the similar area for the Negative connection for >> the 3 battery banks, but a different bolt to the engine case. Several >> appliances including the breaker panels, ACR, battery charger, water >> heater, fuel tank, etc require a ground and I'm using a 6 awg green wire >> from the engine to a large Blue Sea busbar. Then connected the grounds to >> it. >> >> I've also run a 2awg wire from the mast step to the keel bolt and to one >> of the stanchion bases from underneath for lightning protection. However I >> kept that all separated and not connected to the grounding. >> >> Make sense? Or am I missing something? Again, happy to send my diagram >> for review. >> >> Regards, >> Brian >> South FL >> >> _______________________________________________ >> >> Thanks everyone for supporting this list with your contributions. Each and >> every one is greatly appreciated. If you want to support the list - use >> PayPal to send contribution -- https://www.paypal.me/stumurray >> >> _______________________________________________ >> CnC-List mailing list >> CnC-List@cnc-list.com >> http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >> >> >> >> >> -- >> Brian Davis >> 1980 C&C Landfall 38 >> "Nina" >> Southeast Florida >> >> _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > -- Excuse the brevity. Sent from my phone.
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
