I'm looking at fuses. My bus driving side takes regular full size blade fuses. This is not a problem.
The stuff I'm putting in is a bit of a mosh mash. Before I go further, I'd like to standardize. Right now the circuits I've installed in the console are fused with a mix of 6x30 glass fuses and blade fuses - all with individual inline holders.
The house side hasn't yet got fuses though in my battery pack I have inline 6x30 glass fuses. I've also just attached a 4 fuse 6x30 holder to the wall.
In my spares box I have a lot of 5x20 panel mount fuse holders. I'd thought of putting those in the empty switch positions on the console until I found they were bigger than the existing holes.
It's hard with no Radio Shack to find anywhere with a good selection of any kind of fuse. I know blade fuses (I'd so like standardize on blade fuses) come in 1a and 3A values but I need 0.5A, 2.5A, 3.5A. I can fund those easily in 6x30 and 5x20 glass fuses.
My method of finding most of my fuse values is either by knowing from what the equipment says or by starting with a high value and lowering it until the equipment blows the fuse. I also like to fuse each individual circuit. For example, each socket in my 120v system has its own 15A breaker.
Any suggestion on real world fuse sources?
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.05 an amp? Is that a half an amp? ::)
Quote from: muldoonman on August 06, 2017, 06:44:38 AM
.05 an amp? Is that a half an amp? ::)
I don't know where you found 0.05 amp fuses. Now those must be truly unique!
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Why do you need such small fuses? The fuse is rated to protect the wire. If you are using 14 gauge wire, make all the fuses 15 amps as standard. If you are using 16 gauge wire, use all 10 amp fuses, 12 gauge use 20 amp, 10 gauge use 30 amp, and so on. Your method of fusing based on load is contrary to electrical design methodology. First thing - don't fuse every single load separately. Have maybe two fuses for all 12v lighting needs, for example. Second thing - rate the fuse based on the wire. Third thing - keep track of ground current. If you local ground your 12v to the chassis, no problem if your battery ground connection is appropriately sized. If you home-run ground wires to a bus, the master ground from the bus to the chassis/battery has to be sized for the anticipated total load. Fourth thing - consider a master fuse between the battery and the distribution fuses. Exactly the same as the master 100 amp or 200 amp breaker in your house. Use a breaker for it, not a fuse. The way you are doing it now may seem good, but is actually designed to fail a lot. Kind of designing in as many failure points as you can, and making each one as delicate as possible.
Cut out the inline fuses and centralize your fuses with a block like this http://www.wiringproducts.com/6-circuit-ato-atc-fuse-block.html?gclid=Cj0KCQjw_JrMBRDPARIsACis1Hz8NnsttKyh3J-2N7Rx8HvN9YbE2PowzdCO9pPfuP-1RAX_L5GK81MaAluNEALw_wcB (http://www.wiringproducts.com/6-circuit-ato-atc-fuse-block.html?gclid=Cj0KCQjw_JrMBRDPARIsACis1Hz8NnsttKyh3J-2N7Rx8HvN9YbE2PowzdCO9pPfuP-1RAX_L5GK81MaAluNEALw_wcB)
Quote from: Zephod on August 06, 2017, 07:20:38 AM
I don't know where you found 0.05 amp fuses. Now those must be truly unique!
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"It's hard with no Radio Shack to find anywhere with a good selection of any kind of fuse. I know blade fuses (I'd so like standardize on blade fuses) come in 1a and 3A values but I need 0.5A, 2.5A, 3.5A. I can fund those easily in 6x30 and 5x20 glass fuses."
I think that's where I found it.
Quote from: muldoonman on August 06, 2017, 08:05:16 AM
"It's hard with no Radio Shack to find anywhere with a good selection of any kind of fuse. I know blade fuses (I'd so like standardize on blade fuses) come in 1a and 3A values but I need 0.5A, 2.5A, 3.5A. I can fund those easily in 6x30 and 5x20 glass fuses."
I think that's where I found it.
Ummm.... I wrote 0.5 but not 0.05...
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Quote from: bevans6 on August 06, 2017, 07:29:11 AM
Why do you need such small fuses? The fuse is rated to protect the wire. If you are using 14 gauge wire, make all the fuses 15 amps as standard. If you are using 16 gauge wire, use all 10 amp fuses, 12 gauge use 20 amp, 10 gauge use 30 amp, and so on. Your method of fusing based on load is contrary to electrical design methodology. First thing - don't fuse every single load separately. Have maybe two fuses for all 12v lighting needs, for example. Second thing - rate the fuse based on the wire. Third thing - keep track of ground current. If you local ground your 12v to the chassis, no problem if your battery ground connection is appropriately sized. If you home-run ground wires to a bus, the master ground from the bus to the chassis/battery has to be sized for the anticipated total load. Fourth thing - consider a master fuse between the battery and the distribution fuses. Exactly the same as the master 100 amp or 200 amp breaker in your house. Use a breaker for it, not a fuse. The way you are doing it now may seem good, but is actually designed to fail a lot. Kind of designing in as many failure points as you can, and making each one as delicate as possible.
Two reasons. I use a small fuse on the fans because the fan wiring is minuscule. I've never seen such fine wires. The other reason is I'm basing it on fan load. If a 0.5a fan suddenly starts using 1a, there's a problem and I need it to stop before there's a fire.
I'm running the chassis as a negative ground for all but the solar panels. The solar connection is the only negative wire that'll run the length of the bus. The others are the wires coming from my devices. For example, with the front cabin fan, that's mounted on a wooden beam. I've passed the wire through a wooden partition and that just goes straight into the power supply. That'll get a fuse soon.
With my 120V, the chassis is earthed from the main breaker box. I have a main breaker and a distribution panel. Now the reason for that is I started with the main breaker in a cable compartment that the previous owner had installed under the bus. Eventually I did away with that compartment so the two now sit side by side. It's wired in a non standard way - It's a dual breaker so when it trips, it'll cut off both live and neutral simultaneously.that just seemed safer in a steel skinned vehicle.
The underbus battery when I install that, will have a 20A fuse on the negative side as it connects to the chassis. Getting under the bus in the pouring rain to change that will be fun!
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Quote from: TomC on August 06, 2017, 07:37:27 AM
Cut out the inline fuses and centralize your fuses with a block like this http://www.wiringproducts.com/6-circuit-ato-atc-fuse-block.html?gclid=Cj0KCQjw_JrMBRDPARIsACis1Hz8NnsttKyh3J-2N7Rx8HvN9YbE2PowzdCO9pPfuP-1RAX_L5GK81MaAluNEALw_wcB (http://www.wiringproducts.com/6-circuit-ato-atc-fuse-block.html?gclid=Cj0KCQjw_JrMBRDPARIsACis1Hz8NnsttKyh3J-2N7Rx8HvN9YbE2PowzdCO9pPfuP-1RAX_L5GK81MaAluNEALw_wcB)
I'd love to do away with the inline fuses in the console but there's nowhere safe to put a fuse block unless I run all the wiring out of the console and back in again. That would make it even more of a rat nest than Carpenter created.
I'll keep that one in mind. I like that fuse block!
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"Two reasons. I use a small fuse on the fans because the fan wiring is minuscule. I've never seen such fine wires. The other reason is I'm basing it on fan load. If a 0.5a fan suddenly starts using 1a, there's a problem and I need it to stop before there's a fire."
That's a good reason, twice. One is you are protecting the small wiring leading to the fan, and second you are using the fuse as a control device in addition to a protection device.
" It's wired in a non standard way - It's a dual breaker so when it trips, it'll cut off both live and neutral simultaneously.that just seemed safer in a steel skinned vehicle."
I see nothing wrong with that, it's exactly what ATS switches do - disconnect both live and neutral at the same time.
"The underbus battery when I install that, will have a 20A fuse on the negative side as it connects to the chassis. Getting under the bus in the pouring rain to change that will be fun!"
Normal practice is to never fuse the ground connection. If you do, consider using an auto-reset breaker. With that said, there is nothing inherently wrong with fusing the ground connection of a battery aside from introducing a failure point, presuming you fuse the positive side coming out of the battery.
Quote from: Zephod on August 06, 2017, 08:14:39 AM
Ummm.... I wrote 0.5 but not 0.05...
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Heck even 12 volts DC at 43 watts is a little over 3.5 amps in my calculations. What can you power at 43 watts? At .05 amps that would be 6 watts. That ain't a big lightbulb. ;D
Quote from: muldoonman on August 06, 2017, 09:42:49 AM
Heck even 12 volts DC at 43 watts is a little over 3.5 amps in my calculations. What can you power at 43 watts? At .05 amps that would be 6 watts. That ain't a big lightbulb. ;D
If you choose to go with choose blocks like Tom mentioned, head over top the local pick and pull. Find one that suits your needs. May find plenty other inlines for stuff.
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Quote from: windtrader on August 06, 2017, 10:02:17 AM
If you choose to go with choose blocks like Tom mentioned, head over top the local pick and pull. Find one that suits your needs. May find plenty other inlines for stuff.
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think i'll stick with my Old electric panel with round, glass screw-in type fuses running my bus. :D
In the end, based on two important facts:
1. I already have a fuse holder for 4 glass fuses.
2. I can get glass fuses in 0.5A values
I decided to stick with glass fuses.
(https://uploads.tapatalk-cdn.com/20170806/79411796e652bf6379c491ad88f21762.jpg)
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Quote from: Zephod on August 06, 2017, 11:51:17 AM
In the end, based on two important facts:
1. I already have a fuse holder for 4 glass fuses.
2. I can get glass fuses in 0.5A values
I decided to stick with glass fuses.
(https://uploads.tapatalk-cdn.com/20170806/79411796e652bf6379c491ad88f21762.jpg)
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Don't know exactly where you are located, but if you can find where the local ham radio guys get parts you should be able to get a good selection.
I recently got a Blue Sea fuse panel and really like it. Has built-in ground buss and splits the bladed fuses into two separate groups.
1964 PD4106-2412
I use ATC fuse blocks for all DC stuff since that is what the bus wiring uses. I probably have at least a dozen of each size. Delcity used to require minimum orders and I would add cheap ATC fuses to my order to meet the minimum.
Quote from: bevans6 on August 06, 2017, 08:45:11 AM
Normal practice is to never fuse the ground connection. If you do, consider using an auto-reset breaker. With that said, there is nothing inherently wrong with fusing the ground connection of a battery aside from introducing a failure point, presuming you fuse the positive side coming out of the battery.
Some years ago when Sean Welsh was contributing to this forum he advocated using catastrophe fuses on the negative side of house battery banks. On his cogent advice (and he certainly knows more about such matters than me!) I've done the same - I have a quick-blow 300-amp Class T fuse on the negative of each battery bank's house output. For individual load protection I'll still also use fuses or breakers on the positive of each DC house circuit.
John
While catastrophe fuses in the grounds of a house back make sense if it's just a house bank, if you set up to bridge to boost start batteries they could be a problem with starting current loads. Just to be aware if you do that.
Quote from: bevans6 on August 07, 2017, 04:06:04 AM
While catastrophe fuses in the grounds of a house back make sense if it's just a house bank, if you set up to bridge to boost start batteries they could be a problem with starting current loads. Just to be aware if you do that.
I've taken care of that possibility by having two Blue Sea 9001 switches for the starter boost connection, one for positive and the other for negative. This way if I'm boosting the start batteries the negative is also connected directly to the starter, bypassing the expensive ($45 each!) Class T fuses. I don't know exactly what the current draw is to start my engine, but I assume it's briefly more than the fuses' 600 combined amps.
John
The fuses are in series with the battery, you don't add amps in series circuits. If you have two 300 amp fuses in series, you have a 300 amp fuse. If fuses are in parallel, they share the current between them.
Brian
Quote from: bevans6 on August 07, 2017, 07:08:07 AM
The fuses are in series with the battery, you don't add amps in series circuits. If you have two 300 amp fuses in series, you have a 300 amp fuse. If fuses are in parallel, they share the current between them.
Brian
Two independent battery banks, each with its own 300A catastrophe fuse, both banks available to boost the starter if needed (or just one bank or the other if I choose).
John
That makes sense! ;D