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SanDiegoChip 10-25-2010 05:35 PM

Fuse size for fuse panel?
So we are installing a blade fuse panel. I got it in position and along with some other components and then happened to look at the instructions for the blade fuse block. Shouldn’t of done that! It says I need a 150 amp fuse max size for the fuse panel. OK I looked at them in the store and there is a lot of different sizes of fuses. Should I just put in the max size or how can I tell what my needs are?

erps 10-25-2010 05:40 PM

I would need to read the directions, but maybe what they meant was that the wire supplying the power to the panel should be big enough to handle at least 150 amps and fused between the battery and the panel with a 150 amp fuse?

I count 12 fuse blocks on that panel. If they all had 10 amp circuits that ran at the same time, that's 120 amps. (unlikely that would ever happen, but you need to plan for the worst)

tommays 10-25-2010 05:56 PM


A few questions before you get to far

1. how are you holding down the battery's ?

2.The locker with the battery's would not seem to be the most dry and corrosion free place for the fuse panels ?

Stillraining 10-25-2010 05:58 PM

Yep Ray has the answer..Its in case of a major short to disconnect the batteries completely...It will be a separate fuse mounted close to the battry bank.|328|296553&id=823925

mitiempo 10-25-2010 05:59 PM

ATO/ATC fuses have a maximum size of 30 amps.

Fuses are to protect the wire, not the item at the end of it. The exception to this might be low draw electronics that use a smaller fuse. If using 14 awg wire which is pretty normal, 15 amps is appropriate. Thar is why all Blue Seas circuit breaker panels come standard with 15 amp breakers. The maximum rating for the fuse block is 100 amps.

I have no idea where you read 150 amps.

mitiempo 10-25-2010 06:05 PM

Tommay makes a good point. That is not a good place for either the fuse block or the main switch. In an emergency - shorted battery for instance - you need to reach the main switch. It should not be in the immediate vicinity of the batteries. And corrosion from the batteries will not be good for either the switch or the fuse block. Or any bus excepting the maxi bus on the left.

I try to keep all wire connections (other than heavy wire buses) as high as possible, usually around counter height. Exceptions are bilge pumps, settee front lights, and engine wiring where necessary. No small gauge wires run in the bilge except for bilge pump and transducer wiring.

And holding down the batteries?

Stu Jackson 10-25-2010 08:55 PM

Sorry to blow your entire new electrical design, but the guys are right. Get those items (fuse block and switch) out of the battery box. Even if vented, it's not a good idea to have those things in there. You could keep the large bus bars, but the smaller items will die in there, very very soon.

sailingdog 10-25-2010 09:10 PM

If there's an electrical fire near the batteries... you really don't want to have to reach over them to shut them off...since you'll give the fire a lot more oxygen...

You really want to strap the batteries down or install a wooden bar to hold them down. You really should put covers on the positive terminals, if not both sets.

It would also make a lot more sense to have the battery cables go to the bus bars in a different area of the boat and have the fuse panel and switch located there. It would make it a lot easier to work on them and not risk accidentally shorting the batteries.

BTW, the ATO/ATC fuses go up to 40 amps, not 30. :D

mitiempo 10-25-2010 09:27 PM

Really? Both Ancor and Blue Seas max out at 30 amp.

sailingdog 10-25-2010 09:50 PM


Originally Posted by mitiempo (Post 659089)
Really? Both Ancor and Blue Seas max out at 30 amp.

Fuses, ATC Style Fuses, Taps, Holders | TESSCO 800 472 7373

ATO / ATC Blade Fuses, 1A, 2A, at huge discounts

Yup... 40 amps.

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