Fuse panel upgrade to ATO type

targa80 · targa80's Garage

There have been several other threads on upgrading the fuse panel to the ATO type fuse. I have been wanting to do this and have been searching the web for suitable parts to do the job. I have found a fuse holder made by littlefuse that can be ordered at mouser.com.

The fuse holder is capable of being snap-mounted from the rear to a panel with the corrct hole size also the fuseholders interlock for multiple mounting. They have two types one is rated up to 20 amps and the second is rated for 25/30 amps. The wires are connected to spade terminals from the back. The width of each fuse holder is just under 1/2 inch. The old fuse block is 12 and 3/8 of an inch long. I believe that at least 24 fuse holders can fit in the same space as the old type.

I just ordered sixteen of the 20 amp and ten of the 30 amp holders along with fuses and an assortment of male female spade terminals. The total cost is $62.50 without the shipping. The dimensions of the fuse holder are 1.2" L X .4" W X 1.46" D If anyone is interested the mouser part numbers are 5768-55300 for the 20amp and 5768-55400 for the 30 amp. They have a data sheet and picture in a PDF file.

mtelliott · 11-30-2004, 12:55 PM

Are you planning on replacing the entire fuse block? I've been sent dimmensions for replacing the entire panel with a new that holds ATO fuses but haven't attempted to replicate yet. What always gets me is which one's to splice together.

What's your plan? Are you going to replace the fuse blocks with your own creation or what?

RallyJon · 11-30-2004, 01:15 PM

Quote:

The wires are connected to spade terminals from the back.

Isn't that a big problem? You have to mount the whole thing set off from the body by an inch or so for clearance, plus maintain some way of disconnecting everything to get around back to the spade lugs if needed.

randywebb · 11-30-2004, 02:20 PM

What we need is a modern fuse holder that has the same size and screw terminal layout as the ones already in there - that would give us an easy install.

I'm sure you could sell 1,000 of these -- and surely somebody would do up a production run for that number.

toolman · toolman's Garage

I'd buy one right now if I could.

fred cook · fred cook's Garage

Here are a couple of pictures of the fuse conversion that I did on my 1980 SC. The first picture is of the mounting plate (made from aluminum sheet) with the holders installed. Note that the terminals are on the side, thus easy to access once installed in the car.

The next picture is the completed fuse panel as installed mounted in place of the original fuse holders.

The hardest part of doing this conversion is identifying all the jumpers that are hardwired to the back of the original fuse holders and in some cases done with a piece of wire from terminal to terminal. Also, be sure to strip the wire ends back about 1/4 of an inch to eliminate any corrosion that may have grown on the wire ends. Most important of all, tag the wires as your remove them from the original fuse holders. Once all the wires are removed, it would be a nightmare to try to get everything in the right place without the tags. If anyone would like to build an installation like the one I did, send me a pm with your email address and I will send back some drawings and wiring info that I put together.

Fred Cook
'80 911SC coupe

RallyJon · 11-30-2004, 06:43 PM

Fred: this one, right? Did you get them from www.vehicle-wiring-products.co.uk or is there a U.S. vendor?

Brother · 11-30-2004, 07:10 PM

Pat,

Why not go with the mini fuses? I think I might try the same thing. I think I'll start with the ones in the engine bay first.

Glasgow 911SC · Glasgow 911SC's Garage

Quote:

Originally posted by RallyJon
Fred: this one, right? Did you get them from www.vehicle-wiring-products.co.uk or is there a U.S. vendor?

Just a word of warning about these holders. I ordered a few of them to update my rear fuse panel. The heated rear screen melted them without blowing the fuse. They must only be 20amp holders.

fred cook · fred cook's Garage

Nope, that's not the same as the ones I used. Mine came from Norway via Ove (a PP board member). They cost about $1 each plus shipping. They are rated at 20 amps but I haven't had one melt or cause any trouble thus far.

Fred Cook
'80 911SC coupe

CBRacerX · CBRacerX's Garage

Fred - Nice job!!!

I'm not ready to tackle that yet, but I can see it coming!

Chris

Brother · 04-06-2005, 05:25 AM

nice

Wil Ferch · 04-06-2005, 06:22 AM

Fred has the text book example of how this should be done...

When ordering holders, two points:
- amp rating....20A is typical but some of our circuits require 30A...either upgrade or separate the load.

- each fuse holder should allow individual input /output....some "boards" use a ganged input which isn't correct for our application....

Wil

vizail · 04-07-2005, 06:47 AM

Fred
Very nice update/modification. But how come the fuse holders only rate 20amp?. Is there an Alternative fuse holder that can be rated more that 40 amps?

Cordially
Vic

}{arlequin · }{arlequin's Garage

great job Fred. That's something I should get started on as well.

vizail · 04-07-2005, 01:36 PM

Just send you a PM

Vic

fred cook · fred cook's Garage

Sorry guys, not trying to ignore your requests, but I've been off camping for a few days. When I get back to the house I will send the fuse / wiring info out to all the new requests.

fred cook · fred cook's Garage

The company that makes the 20 amp fuse holders that I used (Zirman) also has a 35 amp bakelite version but I have not been able to find a vendor that carries them. They are available from the factory but that would take a $5,000 minimum order!

The only fuse position that I found that pulled over 15 amps is the one for the evaporator and front condensor fans. I just separated them to work off two fuses. If you have high wattage headlight bulbs, best to add the headlight relay conversion. The conversion that I did allows room for 24 fuses, 3 more than stock and the stock cover will still fit over the holders. I have had this conversion in the car for a little over a year and have had to replace one fuse holder. It was the one for the fuel pump relay fuse. It got overheated because of a poorly done connection (my fault) on a short wire that was difficult to work with. Once I replaced the end connector properly there have been no further problems.

RoninLB · 04-10-2005, 12:01 AM

Fred did a great job with big dedication imo.

I've been interested in up-grading the stock crap myself. I kinda lean towards Cole Hersee and Blue Sea Systems. The highest amp on the CH is 25amp and routine on the BSS is 30amp. The best contacts I've been able to find are tin plated copper. I'd be interested if anyone has found silver plated copper.

thx

911SCfanatic · 911SCfanatic's Garage

The fuse upgrade is going into my '72 project along with relocating the blocks and battery to the smuggler's box. Thanks for the info and be sure to post more details as you get them.