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Old 07-12-2006, 01:45   #16
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Darryl, I was supposed to PM you and forgot. Go to any "PowerBase" and get them to charge back to my account at Independant here. They are a PowerBase dealer. That's where I got confused. I knew they were NZ wide in some way.
You will get those heatshrink terminations for about half that price. Or I should say, they come in a packet of ten for about twice the price.
Pete, remember that as well. If ya need anything elelctrical, give me a yell and I will set ou up with the details. I get about 10-15% off trade.

Charlie, the mega is a valueble tool, but you have to weigh the price up against the cost of getting someone to check your boat for you and what stuff you have at home to check as well. It's main job is to test insulation break down. It is good for detecting if an extension cord is faulty. Here in NZ, if any electrical appliance or corad is serviced, the service person MUST carry out a mega test to ensure the insulation is safe and the appliance is safely earthed. It is amasing the number of extension cables from building sites I dumped because of a little pinhole in the insulation. The test was to drop the cable in a bucket of water with both plug and socket out of course and do the test. It was just like a cord lying on a worksite in the rain.
Pete, you don't apply the Mega across an electronic device by the way. You are only testing the insulation and continuity of the conductors. Don't place the thing across the phase and neutral. That would result in a not so good test outcome ;-) Most mega voltages are 500-600V, only a few special ones test in the 1000V range.
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Old 07-12-2006, 08:52   #17
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Charlie, I don't know how far into the desert you might be but most utility companies will come out to inspect your wiring, at least up to the junction box, for free. If things are slow sometimes the guys will also offer advice and take a peek further, I've found it is always worth a call to ask them first. The worst they'll do is say "No."

On tracking down domestic power vampires, I got a gizmo called a "Killer Watt". A white box with a display and four buttons on it, that plugs into any "110" outlet and shows the amount of power actually used. It will handle up to a 15A load, and it shows instant load and totalized power use, so you can plug it into things like a refrigerator and let it run for 24 hours and see how many watts the device actually used over 24 hours.

Very nice little box but I'm done testing now, if it interests you...send me a PM or email and we can both skip enriching eBay.<G>
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Old 07-12-2006, 09:05   #18
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Hello Hello:

(Sounds Like Brit comedy) I don't live too far out in the sticks but I bought a '70's vintage mobil home and we are getting outrageous electrical bills. The problem is when I look at the wiring it is such a rats nest that I have no desire to fix it b/c I'm in the process of building a house, actually near done, and we are just going to scarp the mobile home. Problem is that we are bringing power in from a new source but the old meter will still service the barn, the garage, and a well. I'm thinking that a Megger would help me to tell whether or not I need to replace the underground wiring or not.

PM me cost and model of the Killer Watt I might be interested.
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Old 07-12-2006, 09:36   #19
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BritCom...Could be worse.<G> PM sent by email, in theory.

A lot of rural powerlines have been run very casually, I've heard from folks who have RFI problems because of bad wiring and bad grounds, and even ones that have had livestock electrified by the problem. In what I assume is "better" damper soil than you have out there, so that's more of a problem for them. Split sources with multiple grounds CAN be problematic. Someone needs to look over the whole thing, but I'd bet your local power company can send someone out free instead of buying a megameter. Slip the guy a twenty and he'll probably be glad to check out anything else the cables run to.<G>
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Old 07-12-2006, 12:40   #20
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Thanks for the offer Alan,
fortunately the jobs done. I will just have to get Paula to work that little bit harder to pay Burnscos account
Got an awsome ratchet crimper from Dick Smith. Does a heaps better job than my old basic one.
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Old 10-12-2006, 11:55   #21
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Gord, or anyone else for that matter. With respect to the method of joining different gauge wire, what about terminal strips with appropriatly sized ring terminals properly affixed, strips mounted high and hosed with anticorrosive spray or fed through rubber centre type strain reliefs into a sealed plastic junction box? Any reason not to do that? Other than extra expense? I find that terminal strips and allweather junction boxes keep things quite neat, are easy to label clearly and prevent strain on connectors from excess motion completely.
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Old 10-12-2006, 12:14   #22
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If I understand you correctly, it's called a Buss Bar. You take a "primary' feed to an area and then take "sub" feeds from this to the individual equipment. Each individual feed requires a fuse located at the Buss sized aproapriatly for the equipment and wire size.
This is very acceptable as long as the primary common originates from the common earth point of the vessel. I have about four variouse Buss locations, with Common and positive in a sealed ABS Plastic box. All terminations are made in that and run through glands that are also sealed with a sealnat to ensure total water tightness.
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Old 10-12-2006, 12:19   #23
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yotphix, that's what terminal strips and junction boxes were made for. You'll often find exactly that to join an engine harness to an instrument panel harness, etc. where a larger number of wires all have to make a change.

But for a single connection? You can buy those same nifty inexpensive (in comparison<G>) waterproof adhesive-lined heat-shrink crimps in split sizes. One side is 10/12g, the other side 14/16g. Or 14/16 with 18/20.

For a single connection I'll cheat, i.e. to join a 12g to a 14g I'll use a 12g crimp splice, and double up the 14g wire in the other side so it crimps securely. The glue seems to set just as nicely, but I'll add some extra external waterproofing just to make sure nothing creeps between the wires.
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Old 10-12-2006, 12:30   #24
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Wheels, I found a nice alternative to a Buss bar a couple of years ago. I needed to split the main battery negative (dare I just call it the ground?<G>) where it supplied everything at the breaker panels. I didn't want to use terminal bars and ring terminals, because rings mean any time you remove something there's a loose screw to fall into the bilge. And spade terminals are considered (right or wrong) insecure, they can work out.

So I found a commercial supplier of aluminum distribution blocks. One side has some big fat holes in it, to insert the primary cable(s). The other side has a row(s) of smaller holes, to accomodate loads.

Each of the holes (for loads/feeds) has a threaded hole tapped into it at a right angle, where a captive screw can be tightened down to trap the wire that is in the hole. Result? The screws are captive, never need to be removed all the way. The wires can be bare, no crimps or terminals needed on them. The only accomodation I made on them was to add antiseize in every hole (thread and other) to make sure there's no problem from the aluminum and copper in the marine environment.

So far...Probably against every marine code there is, but they've been perfectly robust and well behaved. Only problem was from a passing diesel mechanic who said "Holy **it! Where's the nuclear reactor?!" because the distribution blocks, smallest the vendor made, are a bit oversize for the boat. But man, did they make the wiring job simpler than anything else I've ever used.

Maybe I should start machining them out of marine alloys and peddling them to the small craft trade, huh?<G>
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Old 14-12-2006, 16:35   #25
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Hellosailor... In your system, are you crimping on the bare wires? If so I'd be worried that now water can wick up into the wire strands and corrode the be-jezuz outta' it. (Stranded wire wicks just like end grain wood)

If you want to use a system like this, soldering the ends of the wires -before- you insert them would probibly go a long way for sealing them. Kinda' like epoxy on the end grain on wood to seal it.

Also, maybe I missed this but heatshink precoated with epoxy is very common and availble. Digi-Key Corporation - USA Home Page etc.

Actually, boat wiring is one of my favorite jobs. I guess I'm wierd that way..

Hope this helps!

Edit : Creepy, you put in a link and it replaces it with where the link goes to..

Edit 2 : Lets see if that works on my home page? Bionic Donkeys

Edit 3 : Wow it does! Man this is a wierd world we live in.

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Old 14-12-2006, 19:54   #26
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Jim-
"are you crimping on the bare wires? No, not at all. The wire ends may be unsealed, but they are fully tinned wires and the actual bare ends are always coated with something. Silicon jelly where crimped in plain crimps, or nickel/copper antiseize where locked down in the distribution bus. Where the crimps are available in adhesive lined form, I still use silicon jelly *sparingly* in the portion that the adhesive won't be touching, i.e. from the open metal end.
"water can wick up into the wire strands and corrode" Which is why you only want fully tinned wire in a boat.

"soldering the ends of the wires -before- you insert them would probibly go a long way for sealing them." It would ruin the crimp, by changing the compressibility and fit of the bundle, and opening the door to mixed metal galvanic problems.

"Also, maybe I missed this but heatshink precoated with epoxy is very common" Are you sure about that? Adhesive lined heat shrink, yes. But not epoxy, epoxy is a 2-part material that is not heat set and not used in crimps at all, AFAIK.

I've also been known to either be generous with silicon jelly (where there has to be repeated access) or spray with BoeShield (or similar) or, in the case of the breaker strips where "we shouldn't ever have to redo them" but we know that one day we certainly shall <G> I coated them with multiple coats of liquid vinyl instead. That's a permanent seal which can be peeled back when and if it has to be.

Hot wax (aka "glue gun") and self-vulcanizing butyl or silicon tape are also good things for bad places.
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Old 15-12-2006, 02:17   #27
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Aluminium buss bars will work, but are not the best. If youa re going to make anything, use a strip of brass square. The Buss bar type I use has a hole in it for the wire and a set screw that clamps down on the wire. the better version of that is the one that has a flat blade under the set screw that clamps against the wire. The flat blade ensures a large contact area and also ensure the set screw does not cut through the wire.
You are also correct that you do not solder wires that are going to be held by a set screw. The soft solder stops the "spring" action of the wire and if the screw should come loose by a fraction, the entire joint looses proper contact and thus can heat. Plus a soldered wire can be cut through much easier by the set screw.
Solder will not cause corrosion issues due to different metals. Besides, it's what the wire was tinned with most likely anyway.
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Old 20-12-2006, 19:59   #28
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Crimp connections and solder connections. Takes me back more years than I care to remember does that! My original trade, time served in the traditional way (one of the last real indentured apprenticeships as they pretty much ceased to exist not longer after) was as an electrical wireman building control cabinets for passenger lifts

This was in the fairly early days of crimp connectors becoming universal - the company I worked for, being a conservative bunch, still favoured solder connections over crimp but the latter was gradually creeping in being much quicker to do and requiring far less skill

However, one major cock-up was that we initially tinned (ie; pre-soldered) the wires before making the crimp in the mistaken belief that this would result in a better connection. It did nothing for the electrical resistance at all and simply led to a high rate of mechanical failures anywhere that the cables were moving around. Cease and desist soldering the wires before crimping and the problem ceased and desisted

Either solder OR crimp, never both!

If you need to stop moisture getting into the joint then cover it with heat shrink sleeving

On the subject of soldered joints, at the risk of losing friends I haven't made yet, it's nowhere near as easy as it looks. It takes a lot of practice and experience to make a good soldered joint and I have to say that I very very rarely see a good soldered joint on any electrical or electronic system that I have occasion to take apart.

Most common problem is inadequate solder flow and/or dry joints (a joint where the solder hasn't bonded with both surfaces) which is usually the result of using silly little 15w irons (anything under 30w is a waste of space and I'd usually want at least 50w), the wrong solder and/or not giving the joint a chance to form properly

The next most common problem is the exact opposite - too much heat or solder with excessive wicking of the solder along the wire, bridging of joints etc. etc.

A crimp joint made with a good ratchet crimp tool (hand tools are OK but better to shell out on a ratchet jobby) and the right size connector for the cable are quick and easy and reliable. A badly made solder joint could have serious consequences as we discovered when a previous owners bodged solder joint came unstuck behind the control panel on our canal boat leading to an electrical fire.

Fortunately, it was rapidly extinguised without major damage but the kicker is that if it had occurred half an hour sooner it would have caught us underground half way through one of the longest tunnels on the English canal system. All because some bozo couldn't be bothered to go to the store and get the right connector and though he could bodge it up with a soldering iron.
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