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C250 Electrical 101

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frejoh
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USA
116 Posts

Initially Posted - 06/07/2005 : 12:38:40

It's nice to be back at the forum again...I'd like to add to the electrical accessories on our 250, but you should rightly assume that I don't really know anything. I'm thinking of adding a radio/CD player and a 12 volt DC connection for TV/portable DVD, etc. using car power cords. Does anyone have a step by step, or a reference book which explains all of this? Electrical questions are not too frequent in the forum, maybe because 250s don't tend to carry a lot of gear like an off-shore cruiser. (Or maybe I'm just out of it.)Any help and advice is appreciated, even up to pay a professional and don't risk your boat or health, but I'm sure many of you guys have done the same.

Fred Johnson
250 WK #669

Edited by - on

moserd
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149 Posts

Response Posted - 06/07/2005 : 13:45:18

I just added a 12 V accessory receptacleto my 2005 WK. This is a VERY easy job, even for someone who is not into electronics (I am a EE). I purchased an inexpensive female 12V power receptacle from Wall Mart. All you need to install is an appropriate size drill bit (I used a wood spade bit), the receptacle and a couple of crimp on connectors.

I choose a receptacle model that was intended to be mounted into a dash and therefore has a locking ring that screws on to hold the receptacle in place.

If you remove the power switch panel via a few screws (you can do this hot, but if you are unsure of yourself you should probably disconnect your battery) you will find a metallic bus bar mounted on the hull. This is your GROUND point. (12 V negative)

Drill your hole to accomodate your new receptacle. I placed mine just to the right of the lower portion of the existing switch panel in order to avoid interferring with anything else. My boat had two spare accessory switches, your boat hopefully will have at least one. I crimped on a terminal lug that fit the lug on one of the spare switches and plugged in the RED wire from the receptacle. This wire should connect to the CENTER conductor on the receptacle (12 V +). Next I crimped on an appropriate connector to the black wire (connects to the side of the receptacle to connect to the GROUND bus bar. Connect this wire up and you are go to go.

Some things to consider though:

Made sure you get the polarity correct! The center conductor of the receptacle goes to the 12V + side of the battery (switch) The outside conductor of the receptacle goes to the negative terminal of the battery.

Make sure that your receptacle is rated for the maximum current of your attached device. Since I am only powering a GPS or a cell phone charger I am not very concerned; however if you plug in a hand held spot light or such you better be sure. Make sure the wire you use is also rated for the expected current.

And last of all, switch; hmmmm.. Can any one tell me about the switches? I suspect that they are actually breakers since I cannot locate any fuses anywhere. Anyone know what the rating might be? (I know, a question answered by a question, sorry about that). I guess I should check out my manual!

Make sure your are fused properly for the application!

Hope this helps, I installed my receptacle in less than an hour and am up and going! :)

Don

Edited by - on

Keith D.
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233 Posts

Response Posted - 06/07/2005 : 20:26:24

The first thing I would do is to replace the switch panel with a marine 12-volt breaker panel. The panel, which comes on a Catalina 250, is only a switch panel and the two fuses on the panel are not even wired up properly. They are in series and should be in parallel. There is just no way to add to the switch panel and it is so cheep to add a breaker panel. I think I paid $38 for a 6-breaker panel. Prior to putting in the breaker panel all you have is two 20A fuses in series so if the first one goes all 12 volt items on your boat will be out.

With the wire sizes Catalina put in if you can draw too much current from most of the wires and melt them before the 20-amp fuse goes. The Catalina 250 was never made to have anything 12volts added to the wiring. I broke the above picture up so you can see what Catalina has given us for 12 volts.

Below is a post of how I resolved this problem, though you don't have to go that far. You can just replace the existing panel with a good breaker panel with the appropriate size breakers. I added the 120 volt AC panel at the same time. Also note all wiring should be marine wiring which is tinned the entire length of the wire to keeps it from corroding and causing fires. The breakers should be marine breakers which are sealed.

http://www.catalina25-250.org/forum/topic.asp?TOPIC_ID=6583

Edited by - on

moserd
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149 Posts

Response Posted - 06/07/2005 : 21:25:40

Keith,

Thanks for the information, my manual has left out a few details that you have provided. I am a little curious about the breaker switch though. I agree that the schematic 'seems' to indicate a series connection but I suspect that this is a 'shorthand' for the drawing. My guess (I will certainly research this one) is that the single breaker switch (on my boat it is a single push switch) has two 20 amp breakers ganged together, one for one set of 'switches' (house lights) and the other for the accessories. Of course, I have no way to determine this for sure without shorting out the accessory switch and see if I still have power on the other side. I will NOT do that of course! :) I do agree that this still seems like a cheap shot on Catalina's part though. I was hoping that each switch was a breaker! :(

The next trip to the boat I will look much closer at this 'breaker'. Maybe I can get a part number, brand, make or such so I can get a proper specification on the breaker.

Don

Edited by - on

frejoh
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116 Posts

Response Posted - 06/08/2005 : 10:53:16

Don and Keith, thanks a million. With no engineering background, I didn't have a clue how much improvement the electrical system needs. Do you think the folks at WM would be able to supply the parts and some advice, or would you shop elsewhere? West is great for specialty marine items, but for common stuff I have done much better at Ace Hardware.

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Keith D.
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233 Posts

Response Posted - 06/08/2005 : 16:45:32

Don the way the diagram shows is how my boat was wired. Someone else also checked their boat and got back to me that theirs was wired the same. My boat had two push button breakers, though the way they were wired only one was in use. Maybe Catalina just removed the second breaker it wasn’t doing any good and they couldn’t put it in parallel because their feed wire from the battery would only handle the 20 amps. (I found only a #14 not a #12 as the diagram states). You can easily see how your panel is wired by just pulling it and looking at the back of the breaker to see if it is a double and where the feed wire goes. The switches are not any kind of breaker; they are just plain spst switches. They are not even a marine quality switch and are a common part, which you can get at any electronic warehouse. I had to replace some of mine, which stopped working, and I had no problem getting the exact replacement switch.
Fred my background is electrical engineering, though since collage 30 years ago I have worked in the computer industry. You will not find much you can use from ACE hardware. As I mentioned in my reply the wire has to be marine wire and the breakers the same. WM does have the parts you need but you can get much better prices elsewhere. I got my breaker panel from sailnet.com at about half the price WM wanted for the exact same panel. I did get a roll of wire from WM because of the small quaintly I needed.

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moserd
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149 Posts

Response Posted - 06/08/2005 : 18:16:56

Keith,

Very interesting. I sent email to Catalina to get further details on my "breaker". It seems that you are correct in your assumption that they have removed 'your' second breaker in my version (2005) and only one breaker is present. Hmmm,,, how disapointing, I went from a Catalina 22 (small boat) to what I thought was a BIG boat. I expected a little more from the 12V system. (and from my BIG bucks!) I guess I am just cheap eh?

Anyway, here is the vendor information from Catalina if anyone is interested:

Seaward Products, 562-699-7997

Thanks,

Don

Edited by - on

DanM
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256 Posts

Response Posted - 06/09/2005 : 08:08:30

You have raised my curiosity about the wiring on my C25. Where can I find that schematic? Three switches need to be on for the instruments. Series wired? Why?

Edited by - on

moserd
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149 Posts

Response Posted - 06/09/2005 : 08:10:57

Dan,

My schematic is in the user's manual. I have had VERY good luck going to the Catalina Web site and sent email requesting information. They have been quick to respond so you may want to give them a try.

Don

Edited by - on

Buzz Maring
Master Marine Consultant

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1762 Posts

Response Posted - 06/09/2005 : 09:51:45

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DanM
 You have raised my curiosity about the wiring on my C25. Where can I find that schematic? Three switches need to be on for the instruments. Series wired? Why? - Dan<hr height="1" noshade id="quote"></blockquote id="quote">
Hi Dan,

Here is a link to the C-25 wiring schematic: [url="http://www.catalina25-250.org/manbro/pictures/owners11.gif"]C-25 wiring[/url]

That wiring diagram is in the "original" version of the C-25 manual, and there is also a "newer" version of the manual ... here is a link: [url="http://www.catalina25-250.org/manbro/manbro.html"]C-25 owner's manuals[/url]

When we've discussed the C-25 wiring in the past, some have indicated that the wiring on their boat doesn't quite match the schematic ... I suppose some boats might have left the factory with slightly different wiring, and in some cases previous owners have modified the wiring. A previous owner rewired my boat ... take a look at all the crap I removed

Edited by - on

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 06/09/2005 : 10:10:10

I don't think the series wiring of the two breakers is a mistake and wouldn't classify the stock panel as wholly inadequate. The home run (wire which supplies the panel) supplied for the basic wiring of the boat is probably too light to support two breakers but the panel having additional switches is designed for adding loading. If the additional loading is minimal, then simply add devices to the lower three swithces... but if the loading is significant, the home run will need upgrading and its then that the second breaker would come into play along with the bottom three switches and should be wired in parallel rather than series.

First, it is overkill to have every device on a seperate breaker. Breakers that also function as switches are expensive. The C250 is produced as a spartan boat with a reasonable price. Those who have more needs are free to upgrade to suit.

Also, standard wire is perfectly fine for fresh water with marine grade required for salt. Perhaps Catalina should have a purchase option for fresh or salt water.

Now, what should a person do to add equipment? If the lower three switches will be used for any device that has significant loading, obviously the existing home run is inadequate. Add another home run sized to meet the needs (#6-10). Wire it between the two breakers as now the wire will be large enough to support both breakers.

With the addition of a DC plugs, blaster pump, cabin fan, sterio, gps, VHF, autopilot and sounder, I added a #8 home run wire between the breakers and cut the existing loose and used it as a supply to a cockpit DC plug for spotlight. I didn't see any need however to add more switches... as most of the devices have their own switch and therefore can be grouped with several other devices on a panel switch.

I'm not suggesting not to consider a marine panel with breakers to switch all devices (especially for salt water), I'm only saying that doing so is probably not necessary for most 250s. The existing panel is designed to handle more loading than the boat was delivered with... with the change to a larger home run. With a larger home run, the breakers can be split rather than being wired in series.

While we're discussing home runs, Catalina did not fuse mine near the battery. IMHO it ought to be and I did.

Edited by - Arlyn Stewart on 06/09/2005 10:32:30

frankr
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256 Posts

Response Posted - 06/09/2005 : 13:08:53

On my 2003 C250K the lowest of the low 3 DC switches control the sparker for the stove. I found this out when I tried to ignite the stove and ended up tracing the wire back to the panel.

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frejoh
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USA
116 Posts

Response Posted - 06/09/2005 : 14:11:05

Arlyn, what guidelines do you use for significant loads? I am thinking that a stereo or portable TV/DVD player would not draw much current, but I'm not at all sure. Do you check the specs on the equipment to see how many amps it requires? I guess that you add up the ampreage requirements of all equipment to determine if you need heavier home run wire and maybe a larger fuse? Lastly, did you install the DC plug similar to Don's installation?

Fred

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DanM
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256 Posts

Response Posted - 06/10/2005 : 07:45:34

Thanks Buzz and Arlen. I printed all the pictures and will compare to what's on my boat. I think mine has been modified, but this will give a starting reference, especially the wire colors and gauge. Upgrading the home run is a good suggestion. Maybe when I report back, should this be transferred to the C25 Forum?

Edited by - on

Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 06/15/2005 : 10:00:21

Fred,

Boat US has a wiring size chart that can be a guide to figuring wire size requirements. The [url="http://www.boatus.com/boattech/CircuitProtect.htm"]wire table [/url]includes instructions on how to calculate amps x wire length to get a number and then categorize that number and come up with a wire size.

For example, for a 20 amp breaker on a home run of 10 feet, the home run is doubled and mulitplied times 20. 10x2x20=400

Looking at the table, the first column offers conservative sizing and is used for important circuits which play into the safe operation of the boat and includes home runs.

400 on the first column shows a required wire size between #10 and #8 but is not too much over the #10 Catalina uses. So, we see that the supplied home run can support one twenty amp breaker but not both, so they have been wired in series.

Now, add up the load requirements. One way to do this is to look at each device and check the specs for its load. Another is to measure the loads, which can be done with an amp meter.

If a dc plug is added that will service a kazillion candle power spot light to illuminate the forward deck while running the blaster pump to wash the crud off the anchor...lets see what the load is? 2 million candle power can draw 120 watts. 120/12=10 amps

Washdown pumps draw between 4-6 amps. So, were looking at 15 amps of draw to haul anchor and vacate that nasty swell anchorage after the wind shifted in the night. This load added to the nav lights, vhf, sounder, gps, chart light, etc will likely run over twenty amps and require an additional home run which can be run to the second breaker and then cutting the line between the two breakers.

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