Raymarine "drain" wire question

[Sunbeam]

I'm installing my new Raymarine A98 chartplotter, and in addition to the main negative wire, it has a "drain" wire. This wire is one of those tiny, hair-like wires. They say to connect it to the RF ground if your boat has one (of course ours do not) or to the negative battery post. Specifically, here is what the Raymarine forum guru posts when folks ask:

Should the vessel be equipped with outboard engine(s) and not be equipped with a bonding cable, then the drain lead should be connected the battery's negative post.

Okay, so that's us. But connected to the battery's negative post?

1) I don't connect things to the battery posts directly unless I absolutely have to, and plus I especially don't on the negative post because the cable from that goes directly to the shunt for the battery monitor *before* any loads (cable goes from shunt to negative bus, where loads attach).

2) Does that really mean anything that GOES to the battery's negative post? Like the negative terminal on the negative bus that C-Dory put in the V-berth "behind" the helm where I already connected the main negative wire from the plotter? I could cut off that ring terminal and do it again but shove the hair-like "drain" wire in there with it before I crimp it, if that would be appropriate. (Otherwise, how the heck do you connect these tiny things?)

Would like to get this up and running, since I'm at Powell and took out my Garmin 2006 OTOH, I don't want to mess anything up.

 

[journey on]

That wire is the chassis ground and it's used to eliminate any RF noise running around inside the unit. With that thought, the best connection for the cable is to an infinite ground, such as the ocean or earth. Your battery is the next best sink, since it has a large capacity to absorb small, high frequency voltages.

The further the connection is made from the battery, the less direct path the ground has to the battery sink. The further from a direct connection, the less the battery looks like an infinite sink. Up to you, and if you have any noise you can move the connection. I usually splice a wire to that chassis ground and either connect it to a bronze through hull fitting or lay it on the bottom of the cockpit floor. In the latter case, I'm supposing that it will inductively couple to the water on which the boat is floating. Others use copper strips. I've not noticed noise, though. Most of the existing devices are digital and it takes a goodly voltage to upset them, say 5 v or so.

The reason the wire has fine strands is that the RF noise at high frequencies travels on the surface of the conductor, no current flows through the wire's center. So that cable has a large surface area relative to it's cross section.

More than you wanted to know.

Boris

 

[Sunbeam]

No worries about too much information - I like knowing how/why things work.

The reason the wire has fine strands is that ...

My "how the heck do I work with this thing" question isn't because it has fine strands, but because the whole darned wire is about the size of a hair. I can't even picture how I would lengthen this to reach the battery.

If I did wire it to the battery, would my shunt/battery monitor still see the current running to the plotter?

Also, I do have a negative bus very close to the battery, connected with about 2 feet of #6 cable... would that be good? Of course there is still the question of how to take a wire that is the size of a hair and connect it to something so it will reach the bus and hook up to it (I don't happen to have any #30 x #8 ring connectors (or whatever size that hair like wire is). The smallest I have are the typical "pink" which I think are 18-22 gauge.

What have others done with the Raymarine "drain" wire?

How would I know if I had RF interference?

Thanks,
Sunbeam

 

[ghone]

Best to wire it as per the manual. Wiring practices are different between US and UK designers. If you go Raymarine it's best to follow all directions on the install even though they may be a little unusual.
George

 

[Sunbeam]

Best to wire it as per the manual. Wiring practices are different between US and UK designers. If you go Raymarine it's best to follow all directions on the install even though they may be a little unusual.
George

I am trying to follow the instructions. But I guess I have two questions:

1) The Raymarine techs on their forum says to take it to the negative battery post on outboard powered boats, but I have found that in reality, sometimes that means literally to the battery post, and other times it means "to something like a negative bus that is connected to the battery but we don't know what you have so we will just say battery post." I don't want to bypass my battery monitor shunt unless I have to.

2) How does one connect a tiny, hair-like wire to a battery post? I don't know what gauge this is, but it makes 22 gauge look like fire hose (my old Garmin has wires like this for NMEA 0183).

I'm not trying to "not do it like I'm supposed to," but there is no obvious right way that I can see, so I just wanted to find out more about what my options were. I also don't know how to work with a wire so small.

 

[Sunbeam]

Doing some web searching... seems I'm not the only one who has questions about this. So I'm confused but not alone (some consolation). I found this tidbit on Panbo in response to a question on drain wire:

"Grounding at more than one location may
produce ground loops, which can cause problems with
communications on the network. In addition to the ground
wire, connect the drain or SHIELD wire at the supply ground
location and NO other place."

That seems like I would want to connect it with the main ground wire in the Raymarine harness (which goes to the negative bus "behind" the helm). At least I think that's what they mean by "supply ground location." In threads in a few other forums, electronics installers also said to put it to the negative ground point. I would just go with the Raymarine forum solution, except that introduces other problems (how to connect tiny wire to battery post; plus having power for chartplotter bypass my battery monitor shunt, when directions for those clearly state that all loads go after the shunt, which is how I have all my wiring now).

 

[olsurfdog]

Sunbeam,
Ah---electronics!!! Not my strong suite!!
A further question: if you end up hooking the wiring harness ground and this " drain" wire up to the same place, why have a separate "drain"? Why don't they just connect them together inside the unit since the go to the same place anyway??
Electronics truly area a mystery!!!
Have you tried Raymarine customer support?

 

[Sunbeam]

Well, on boats with a dedicated RF ground (bigger boats than ours) that's where the drain wire goes. On boats with an inboard (but no RF ground), the drain wire goes to the engine ground, as I understand it. But apparently we have a floating ground on our outboard boats. In other words, there is no "real" ground (again, as I understand it) so we don't really have a way to do the "big boat" way anyway.

Advice on how to hook it up on our boats varies from "to the negative battery post" (problematic with a battery monitor and also with a hair like wire), to "tie it in with the regular negative cable wherever that goes." The latter mentioned by several "real" electronics installers.

Raymarine's own forum has a pre-written answer (in other words they paste it in when someone asks about the drain wire, not that there is anything wrong with that). It's the last bit of that that I quoted in my first post. I just get the feeling that "connect it straight to the negative post" might not actually be the best way to go in all situations (the makers of my battery monitor would probably not recommend that), or the only way to go that is effective. Also, I'm not sure how to physically do it (there is only one cable on my battery's negative post, and it is a #6 cable with a big, beefy lug on the end of it - not sure how to attach a super thin wire).

Again, not trying to go against instructions, but if I had a wire on my battery post for every time it was "recommended," they would be a jumble of a dozen or more wires crowding onto the post. I think sometimes it's just the easy thing to say when they have no idea if you have a bus bar or etc. (?)

I would try calling Raymarine but it's a six-hour round-trip drive to the nearest town with a cell signal for my phone. I already know what I will find if I post on the forum (the stock answer). I figured someone here would know, but maybe not (or they are out boating ). I might just put my Garmin back... they seem to have taken care of this drain feature without requiring a separate connection. But... I was hoping to use the Raymarine here on Powell (especially because one reason I got it was that my Garmin depth sounder died and so I wanted to do something).

 

[Lost Petrel]

How about just using a temporary clamp (alligator clip whatever) to attach it to an easy to get to/best you can find ground and see how the system performs? You may be battling ghosts.

 

[rogerbum]

I've got money that says you can either connect it to the closest negative bus OR leave it completely disconnected and not notice an perceptible difference in operation. In practice, most of the time these things don't really matter. In graduate school and in my post doc, I did a lot RF and microwave engineering to set up experiments. Things that "should" have mattered according to theory, rarely made a big difference. If it were me, I'd connect it the closest negative bus and go about the rest of my day.

 

[Captains Cat]

I'll bet on Roger! That's what I've always done, with all my Raymarine Drains... :shock: The closest negative bus bar will provide sufficient "british grounding" to your systems.

Charlie :thup

 

[Sunbeam]

Thanks! I will start by hooking it up to the negative bus that is already "behind" the helm. That way I can put it in with the "regular" negative in the same 18-22 ring terminal, which also solves the "who has a hair-sized crimp/ring anyway?" problem. If anything odd crops up, I'll keep that in the back of my mind as something that could then be tinkered with. I bet you are right and it will be fine.

I think then I will be able to fire it up. Whee! I can't think of any reason I need the NMEA 0183 wires (yay if so, because... more hair-like wires!). Not having to use those will probably "ease" the price of the Icom M506 when the time comes to add a second VHF with AIS (it uses NMEA 2000 vs. I believe the Standard Horizon 2200 - or whatever number they are up to now- uses NMEA 0183).

Thanks again.

 

[AstoriaDave]

Been puzzling over this micro drain wire and following the discussion. I agree tying into the nearest negative buss is the most expedient solution. The danger is that something also on that buss generates RFI which may affect the unit. Then you will be on a chase to eliminate the RFI from the source. I believe there are small toroids which can be strung on the supply wires exiting the offender which will greatly reduce the interference if you find any.

I have been aboard small boats in which RFI from the ignition system on the engine really hammered the clarity of VHF transmissions, and reception as well, to the point the VHF was almost unusable. I suspect the RFI was caused by a high resistance ground connection in the ignition hookup, and the VHF was bussed along with that connection. Likely yours is a sanitary electrical system, Sunbeam, and you will not have issues.

As to why the drain wire is so small, I suspect Raymarine ran it off a handy hole in the circuit board, and that was the size wire which fit the hole. Better practice would be to run that small wire to a connection strip inside the unit, and exit its housing with something more robust, at least 18 GA, maybe 16 GA. You could do the same, adjacent to the unit, if you felt the small wire was at risk, running to the nearest buss. Naturally, the shorter the overall run to the battery terminal, the less RFI it will pick up. Avoid bundling with other wires, as that could enhance pickup of RFI.

 

[Sunbeam]

Thanks for that additional info. The negative bus that is "behind" the helm currently is the original C-Dory one. Not that there is anything really wrong with it, but I'm going to be replacing that with a nice, new Blue Sea one over the winter.

I would just run the "drain" wire back to my "big" negative bus (which is in the lazarette and fed by a short #6 cable from the shunt via another #6 from the shunt to the house battery), but I just don't have any connectors that go that small. What do people use to, say, butt connect one of these tiny wires to a larger one for the run back aft? It's the same size as the tiny NMEA 0183 wires (is bundled with them).

I'm not keen to just run it to the battery post, for reasons mentioned above, but would be happy to run it back to that "main" negative bus in the lazarette just after the shunt, IF I knew how to put a connector on to extend it. (On the other hand, if I crimp it in with the main negative wire from the chartplotter, then that part is no problem, but it will only go to the negative bus by the helm.)

 

[Sunbeam]

Okay, so here is what I decided to do, at least for now:

1) I discovered that by doubling over the "hair like" wire, it would fit into an 18-22 "pink" ring connector and get a good, solid crimp. So for now I did that (putting it into its own ring connector, not the one with the "normal" negative wire from the plotter), and will run it to the helm negative bus but put it on its own screw, not with other wires.

2) Once I have more wire (my main electrical supplies are not with me here), I may cut off that ring terminal and instead butt connect it to a longer wire (of some yet-to-be-determined larger gauge) and run it back to the lazarette.

3) In the lazarette, I would start by connecting it to my negative bus there (hate to move to battery post unless it is really necessary).

Sunbeam

PS: I had a slight puzzlement when I went to strip that tiny wire and, no matter how careful I was (of course the 22 gauge stripper was too large, so I was using a pocket knife) I kept cutting off the whole thing. After a couple of times of that I knew something was up and looked closer: Aha - the wire insulation extended about 2" past the end of the wire, so I was "stripping" just insulation with no wire ever in there. Duh! I also found that I could just "pull back" the insulation vs. cutting it off (once I started with a fresh cut that had both wire and insulation in it). It's very rubbery insulation and moves easily along the wire.

 

[Sunbeam]

While we are all here, I have one other question, this one related to the positive feed wire for the Raymarine plotter.

Okay, so my Garmin plotter had its own spot on the helm fuse block, with a 5 amp fuse in it. These connect with what I think you call spade connectors (they are tabs and the connectors slide onto them). I neglected to stock any of those in "pink" 18-22 gauge size (I only have blue along).

However. The Raymarine plotter positive lead already has an inline fuse in it, supplied by Raymarine (glass fuse). I can't remember if the Garmin had this or not, but anyway. Can I at least for now just put a ring terminal on the end of this wire (I have 18-22 ring terminals along of the appropriate spec) and connect it to the screw that is the positive post for the fuse block? This will mean it does not have the "fuse block fuse" that the Garmin had, but it will still have its own, Raymarine supplied inline fuse on the positive wire.

If that's not good, I could go to the hardware store and probably get a "sub standard" (for now) spade connector. Although I question what two fuses in a row would do anyway (?).

Thanks,
Sunbeam

 

[potter water]

Using the block is nice, but not necessary. Just hook the wire to the supply side of the block and use the in-line fuse. Get fancy when you get home. My boat is wired such that all electronics are grounded at a negative buss behind the panel. If your's is the same, then grounding the plotter at the same buss behind the helm is just as good as grounding at the Bat terminal. In fact it is better because all nose sensitive and producing equipment is grounded at a common point. And that is what helps control the noise between electronics and controls ground loops, which generate noise. As a rocket scientist, that is my best advice. That is how we do it on spacecraft, and we get to mars okay, so your C-dory should do fine with the plotter grounded at the buss bar behind the helm. I imagine that some of the factory advice is assuming you don't have a gaggle of other electronics, and if not then ground it at the battery. Simple language is good for electronic DIY.

Let us know how it works.

Sadly , Susan and I are home now and no longer on the lake. RATS!! No fun.

 

[Sunbeam]

As a rocket scientist, that is my best advice.

Hard to beat that :wink I think in my next life I will be a rocket scientist just so I can use that line

I imagine that some of the factory advice is assuming you don't have a gaggle of other electronics, and if not then ground it at the battery. Simple language is good for electronic DIY

That's what I was thinking and why I was resisting going straight to the battery post. If I did that every time it was recommended I would have a battery post full of wires! And of course they don't know I have a battery monitor with shunt, etc.

So it sounds like the way I'm doing the negative now should be good: Two separate wires (regular negative plus "drain") each with their own ring terminal, not bundled together, and both connected to a terminal on the negative bus that is associated with the helm wires. I will report back on that later for the benefit of others/general curiosity.

Will run the inline-fused positive to the main power post on the helm bus, at least for now.

Sadly , Susan and I are home now and no longer on the lake. RATS!! No fun.

Darn, come back and we can have a second "mini" CBGT! Looking at the weather I'm thinking of launching Sunday afternoon or early Monday. It looks like a seasonal weather/change type storm is coming through Saturday/Sunday and I'm chicken about being out there during lightning/storm - at least if I can avoid it - of course if one comes along once you are out there that is different and you just adapt. I guess the main fleet for the CBGT will avoid that by taking out before it hits.

 

[colbysmith]

KISS! Too much information and thought going into all this. Our boats are pretty simple and not much "noise" except from the engine electronics maybe. Sunbeam, just hook the drain wire to a negative post on your fuse block, or ignore it. (I'm guessing if you have a drain wire, you also have a shielded cable!) That's what I have done in the past without issue. As for the NMEA networks, I use those wires to get the various units to talk to each other. IE, without those tiny network wires, my radio's AIS receiver wouldn't show targets on my MultiFunction display, and my VHF wouldn't have my position for the DSC! (The last one is a biggy. And probably one of the reason most folks with a DSC radio, don't have access to the DSC!) If you are connecting tiny wires to tiny wires, get some of those button style connectors that squeeze out a little silicone when you close them. (Used many times for phone wire connections.) As for connecting to fuse blocks and the like, use of the red #14 & smaller terminal ends suffices, just as you did. Sounds like you have hooked your stuff up properly, but I'd really encourage you to hook up those tiny NMEA wires also....even though those connections can be kind of confusing. I'm assuming that you have a VHF radio with DSC and would like to know you can depend upon the emergency distress button working! Colby

 

[Sunbeam]

KISS! Too much information and thought going into all this.

The Raymarine manual said to hook up the wire, so if I was going to leave it off, or do it differently (or do as they specified even), I wanted/needed to understand it, simple as that. It's not too much information for me.I do understand completely if you (or others) don't want to think about these things or gather information about them. To each their own. I would prefer not to qualify for your second "S" though just for asking questions!

Our boats are pretty simple and not much "noise" except from the engine electronics maybe. Sunbeam, just hook the drain wire to a negative post on your fuse block, or ignore it.

As I posted, I hooked it up to its own terminal on the helm fuse block (i.e. not bundled with the main negative wire). Good to know that has worked fine for you.

(I'm guessing if you have a drain wire, you also have a shielded cable!)

I don't know, what would a shielded cable look like? The main cable just looks like any other black rubber covered cable to me (are those shielded?)

As for the NMEA networks, I use those wires to get the various units to talk to each other.

I don't think I have any NMEA 0183 things that need to talk to each other (?). My previous Garmin chartplotter used those wires to (I think) talk to the external antenna and to share the depth info with the stand-alone Garmin depth sounder (so it would display on the plotter screen too). But now the new unit has a built-in antenna and it's own built in sounder module. I have kept the stand-alone depth sounder for now, but don't need it to repeat onto the main screen (in fact one thing that helped drive me to a new plotter was that I think that head unit has gone wonky, so I will probably remove it altogether).

IE, without those tiny network wires, my radio's AIS receiver wouldn't show targets on my MultiFunction display, and my VHF wouldn't have my position for the DSC! (The last one is a biggy. And probably one of the reason most folks with a DSC radio, don't have access to the DSC!)

I don't have an AIS receiver yet. My current thinking is that I would get the Icom M506, because then I would have AIS plus a second VHF (which I would ike) and it hooks up via NMEA 2000. My current VHF does not have DSC.

If you are connecting tiny wires to tiny wires, get some of those button style connectors that squeeze out a little silicone when you close them. (Used many times for phone wire connections.)

Ah okay, I had seen those when I was Googling around. For my previous Garmin, we soldered ("we" being a friend of mine who was boating with me and an expert tiny-wire solderer).

As for connecting to fuse blocks and the like, use of the red #14 & smaller terminal ends suffices, just as you did.

Good to know, thanks.

Sounds like you have hooked your stuff up properly, but I'd really encourage you to hook up those tiny NMEA wires also....even though those connections can be kind of confusing.

What would I be hooking them up to is what I'm wondering? I don't think I have anything that would use them now that I no longer have my Garmin chartplotter (?). Since the Icom M506 uses NMEA 2000 I don't believe it would use those wires, right? (I don't have that yet, but when I do get a second radio, I think I will get that instead of the SH 22xx which uses NMEA 0183.)

I did find one area of concern: That is that the Raymarine manual specifies not to have the unit or cables within (IIRC) 3' of a VHF, VHF cable, VHF antenna, or VHF antenna cable. Well swell, my VHF antenna is mounted to the side of the boat about 10" from the plotter! And of course the antenna cable runs right alongside the plotter cabling. Not much I can do about that unless I move the antenna to the cabin top. I've actually been wanting to do that because the antenna where it is now really gets in the way of working the starboard side deck, but have held off as I'm not sure yet if I will do a radar arch or etc., and don't want to move it twice. Hopefully it doesn't have a huge negative effect on the plotter. I'd be interested to know what to watch for if anyone does know what the negative effect would/could be. Would it just be interference when transmitting on the VHF? Would it have lasting effects on the data or chartplotter? Or?

Sunbeam