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hi youtubers jeff cote here  with another session of ask pys  so we've got a boater named mike and  mike asks a good question he's got a 46  grand banks and he's run he has a  conundrum  big word by the way um i think i almost  pronounced it right  and he's got a ferono black box dss one  uh basically a fish finder the black box  sounder is connected to  my pc running tz navigator and here's  where it gets interesting  this black box has two connections to  ground one that with power  shield and one with a lug on the case  what is the best place to ground each of  these  oh this is a tough one isn't it why  multiple negatives  well i remember when i started this  whole world after graduating university  and trying to figure all this stuff out  i didn't understand either to be quite  honest  so there's really two concepts and we're  going to do a special  probably long video on grounds because  it's been requested a numerous times by  you guys the youtubers out there  so what we want to do so you've got this  concept of what's called an rf ground  and a return ground right so you're  going to have a shield  yes connected on the wire so that  basically  everything is sort of grounded to the  battery  but it's also important to have the case  shielded and that's basically what  there's a big distinction between what's  called the non-current  carrying ground and a current carrying  ground right  so one is a return path right that's  actually you're expecting current on and  the other one is really  no current at all it's just a reference  point so  for instance in this case the black box  right  that little lug on the side that needs a  connection  that is to keep everything grounded at  actually  basically zero and it's not we're not  expecting any current on that wire  but sometimes there's a lot of magnetic  interference  right like inductive like when current  goes through a wire  it causes induction regardless right  like there's always a magnetic flux as  current goes through wires  and since there's a lot of wires in  boats and there's a lot of wires close  to one another  one way to alleviate or stop all these  sort of  weirdness or ghosts on the boat is to  have everything properly grounded  and the way to do that is to have a  non-current carrying  grounds connected or the rf grounds  connected to all the  electronic equipment on your boat so you  basically run a small wire  to all these points they all end up  being connected  to a common ground point but you're not  expecting current on that cable  it's just to keep the equipment or the  electronics  at the same potential and so you know a  lot of people don't do it because it  works without it  but then if things are weird and acting  up you know if you don't follow the  instructions we can't really blame the  equipment right we've got to blame  ourselves  right because we didn't follow the  instructions so when we do navigation  system installs  i definitely ask my techs to wire the rf  ground to a non-current carrying  connection that is going to be separate  from the dc  negative connection on that boat  definitely worth doing  thank you for watching this pys video if  you've got further questions please ask  it below or contact  us on our contact form on our website  and don't forget to subscribe thanks  again for watching  English (auto-generated)