Frankieboy Posted June 12, 2011 Report Share Posted June 12, 2011 I need to earth the 240 volt system and know not to mount it to the same bolt as the 12v earth but the question is this: Does the 240v earth have to be mounted as near as possible to the 12v earth, or does it not matter how far apart they are so long as they are both mounted to the shell somewhere? Link to comment Share on other sites More sharing options...
Guest Posted June 12, 2011 Report Share Posted June 12, 2011 I need to earth the 240 volt system and know not to mount it to the same bolt as the 12v earth but the question is this: Does the 240v earth have to be mounted as near as possible to the 12v earth, or does it not matter how far apart they are so long as they are both mounted to the shell somewhere? I believe that the AC and DC earth connections should be bonded to the shell within 75mm of each other. Link to comment Share on other sites More sharing options...
Frankieboy Posted June 12, 2011 Author Report Share Posted June 12, 2011 Perfect, thank you. Oh, I just thought, the 12v earth is to the engine block. Would there be any harm putting the 240v one near there too? Link to comment Share on other sites More sharing options...
blackrose Posted June 12, 2011 Report Share Posted June 12, 2011 (edited) Mine actually uses the same earth stud for both 240v and 12v, but I've heard that this isn't ideal because if the earth stud somehow became disconnected from the hull (corrosion?), it would potentially be unsafe because it leaves the AC and DC earths connected but unearthed. I must get around to putting in a separate stud. Edited June 12, 2011 by blackrose Link to comment Share on other sites More sharing options...
Frankieboy Posted June 12, 2011 Author Report Share Posted June 12, 2011 Yep, will be on a seperate stud, but was just wondering if it was still ok to go on the engine block near the 12v one, or whether I should avoid the engine and put it on nearest point on hul. Link to comment Share on other sites More sharing options...
Chalky Posted June 12, 2011 Report Share Posted June 12, 2011 I've got an 6mm earth stud drilled and tapped into the 4mm steel bulkhead between the engine room and bathroom. It's about 4' away from the 12V earth (which is on the engine) and about 6" away from the 240v distribution unit. I used 10mm green/yellow cable. Link to comment Share on other sites More sharing options...
bottle Posted June 12, 2011 Report Share Posted June 12, 2011 Pedant on: 12v negative 240v earth Pedant off Link to comment Share on other sites More sharing options...
ChrisPy Posted June 12, 2011 Report Share Posted June 12, 2011 Perfect, thank you. Oh, I just thought, the 12v earth is to the engine block. Would there be any harm putting the 240v one near there too? if you have a steel hull, then the 12V negative should be bonded directly to the steel hull (in your case in addition to the engine block, which itself may not be well bonded to the hull). Link to comment Share on other sites More sharing options...
TimD Posted June 13, 2011 Report Share Posted June 13, 2011 provided the earth connections to the hull are sound then it cannot possibly matter how close or how far apart they are. Putting them nearish to one another just makes it easier to locate them both. Link to comment Share on other sites More sharing options...
alan_fincher Posted June 13, 2011 Report Share Posted June 13, 2011 if you have a steel hull, then the 12V negative should be bonded directly to the steel hull (in your case in addition to the engine block, which itself may not be well bonded to the hull). This is, of course, the vital point. No way, (in my view!,) should you be using the engine as a 240 volt earthing point. It must be to the shell itself. Link to comment Share on other sites More sharing options...
Guest Posted June 13, 2011 Report Share Posted June 13, 2011 This is, of course, the vital point. No way, (in my view!,) should you be using the engine as a 240 volt earthing point. It must be to the shell itself. I concur. Link to comment Share on other sites More sharing options...
Big COL Posted June 14, 2011 Report Share Posted June 14, 2011 The vital point is Bonding is there a problem earthing out on the engine and then bonding down to the hull Link to comment Share on other sites More sharing options...
ChrisPy Posted June 14, 2011 Report Share Posted June 14, 2011 yes. the 12VDC negative and the 240VAC earth should be bonded to adjacent points on the hull. if the 12VDC negative goes to the engine, then the same unbroken cable should also go to the hull bonding point without a break. Link to comment Share on other sites More sharing options...
Ex- Member Posted June 15, 2011 Report Share Posted June 15, 2011 (edited) The 12 volt is bonded the other side of the ply in photo, I was also advised to bond 240 volt earth close to the consumer unit which I did. Earth cable attached with M8 nut and bolt through bulkbead with grip washers either side to ensure good contact to bulkhead.I did bear the steel first also then repainted around to tidy up. Edited June 15, 2011 by Julynian Link to comment Share on other sites More sharing options...
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