Do you still need inline fuses with ATO Fuse Block

[Caseyuconn]

I bought a new Blue Seas 12 slot fuse block with buss bar, 100' of 16 gauge tinned wire and lots of connectors to over haul my electrical.
I have been staring at it for the last week trying to wrap my head around the install and have a couple questions.

1. With the new ATO fuse block can I remove the inline fuses from the accessories? i.e. Chartplotter came with an inline fuse, so did the VHF radio. These have a glass fuse on the positive lead. Will the fuse block cover these?

2. Should each accessory have its own slot in the fuse block? If I want my Chartplotter and Depth finder and VHF on the same accessory switch do I run on lead from the fuse block to accessory switch? This confuses me. So would it be fused for the minimum rated of all accessories on that switch?

Im sure Ill have some more questions but these two would help out alot.
Thank you

 

[Grandad]

Re: Do you still need inline fuses with ATO Fuse Block

1. With the new ATO fuse block can I remove the inline fuses from the accessories? i.e. Chartplotter came with an inline fuse, so did the VHF radio. These have a glass fuse on the positive lead. Will the fuse block cover these?

2. Should each accessory have its own slot in the fuse block? If I want my Chartplotter and Depth finder and VHF on the same accessory switch do I run on lead from the fuse block to accessory switch? This confuses me. So would it be fused for the minimum rated of all accessories on that switch?

If you're going to have all 3 devices controlled by a single switch, there are 2 methods:
1. Use a "3-pole" switch (3 sets of contacts controlled by one actuator) with each device fused separately from the new fuse panel. In this case, you could remove the existing 3 inline fuses.
2. Using a single pole switch with sufficient current rating to carry the combined current of all 3 devices. You would feed the switch from a large fuse in the new fuse panel. You would then retain the existing inline fuses for individual protection of each device.

Either way will work fine, but if I needed to control all 3 from one switch, I'd go for the 3 pole switch. This would eliminate additional fuses in series, eliminating the additional fuse contact points that must be kept intact for reliability. - Grandad

 

[bruceb58]

Re: Do you still need inline fuses with ATO Fuse Block

The inline fuses are still necesary. They are typically a lower value because they are actually protecting circuitry inside the device that will be damaged at fairly low currents. You can use seperate circuits from the fuse panel if you wish. If you want to use just noe, just make sure the capacity of that circuit is enough for all devices.

 

[Grandad]

Re: Do you still need inline fuses with ATO Fuse Block

The inline fuses are still necesary. They are typically a lower value because they are actually protecting circuitry inside the device that will be damaged at fairly low currents.

????

 

[Bob_VT]

Re: Do you still need inline fuses with ATO Fuse Block

Many items require their own fuses and it is best to leave them in place.

As an example the VHF radio should be fused on BOTH the + and - side. That is the proper way to fuse a communications piece.

If you already have the fuses at most it will cost you a few more connectors but it is worth it.

You made the right choice using tinned wire.

One other suggestion since you bought all that wire........ LABEL all of your wires to make them easier to trace

 

[bruceb58]

Re: Do you still need inline fuses with ATO Fuse Block

????

Sorry...can't explain it any easier than that!

If you have a depth sounder that has an inline 3A fuse that comes with it and you have it connected to a 15A circuit, you need that 3A fuse to blow if something happens within the depth sounder that draws something more than 3A but less than 15A. Maybe that is clearer.

 

[Grandad]

Re: Do you still need inline fuses with ATO Fuse Block

Sorry...can't explain it any easier than that!

If you have a depth sounder that has an inline 3A fuse that comes with it and you have it connected to a 15A circuit, you need that 3A fuse to blow if something happens within the depth sounder that draws something more than 3A but less than 15A. Maybe that is clearer.

I'm sure the OP recognizes that if he removes a 3 amp inline fuse, he wouldn't replace it with a 15 amp ATO. Why have both? - Grandad

 

[bruceb58]

Re: Do you still need inline fuses with ATO Fuse Block

If the 15A circuit feeds multiple items which it certainly can.

 

[Grandad]

Re: Do you still need inline fuses with ATO Fuse Block

Hi Casey - I hope the miscommunications above aren't confusing you. The best way to protect components is with separate fusing for each. You do this because if one component causes a fuse to blow, you don't lose functionality of anything else. It also cuts down on the troubleshooting to find the problem. Each conductor must be sized adequate to the load its feeding. You only need to put one fuse in a conductor, sized to protect the device its feeding. I would use the size recommended by the component manufacturer. That fuse should be at the supply point (at your panel). You indicated that the manufacturer put an inline fuse in the positive leads only, not the negative. That's a good thing, contrary to the above negative (pun intended) comments.
See http://www.w8ji.com/mobile_ground.htm

Replace the inline fuses with ATO fuses in the manufacturer's recommended size at the new ATO panel. Suitable sizes are readily available.
See www.tripac.com.tw/pdf/passivecomponent/LITTELFUSE/257.pdf

Since you want to switch 3 separate loads with only one switch, you need a 3 pole single throw switch to keep these 3 circuits separated. 3 pole switches are not always available in designer knobs as in other configurations. The most common is a standard "toggle" switch. Many will have double throw contacts and although you need only single throw, the additional functionality shouldn't be a problem. You just don't use all the terminals.
See typicals here http://www.led-switch.com/Miniature Toggle Switch.htm

The following old iboats thread might be of interest to you: http://forums.iboats.com/showthread.php?t=65521

I hope this helps. These threads sometimes start to look like a competition between initially well-meaning individuals. I'm not interested in comparing the length of my deck with others, so if this thread deteriorates and you feel the need for straight talk, you can send me a private message. - Grandad

 

[bruceb58]

Re: Do you still need inline fuses with ATO Fuse Block

You really want to get a waterproof switch if you want to have 3 separate fused circuits supply your 3 components and be able to turn them all off. This may be tough to find. You would be trading the unreliability of inline fuses to the unreliability of a non waterproof switch. I personally don't have a switch for electronics at my helm as I rely on my master switch at the rear of my boat to make sure everything is turned off. No matter what you decide to do with the fuses, I would personally skip the switch.

My depthsounder/GPS unit alone has 2 separate fuses. One for the unit itself and one for the communications bus. Even a 12 slot fuse panel gets filled up fast when trying to separate every fuse out.

These threads sometimes start to look like a competition between initially well-meaning individuals. I'm not interested in comparing the length of my deck with others, so if this thread deteriorates and you feel the need for straight talk, you can send me a private message. - Grandad

And If you really want to get various opinions on how to do things, which is why you posted in the first place on a public forum, keep on posting. It helps you and others as well. The best technical mod on this forum won't answer private technical PMs for this exact reason.

 

[Caseyuconn]

Re: Do you still need inline fuses with ATO Fuse Block

Thank you for all the posts. Very helpful. For clarification I am using Contura waterproof rocker switches. It is a Boston Whaler and came with 3 rocker switches. Nav/Anchor , Bilge, Acc.
I will post my schematic design under a different heading for your review.

 

[bruceb58]

Re: Do you still need inline fuses with ATO Fuse Block

Yes, you are going to have a tough time especially finding 3 pole Contura switches. I know Blue Sea doesn't make one.