Rivers & creeks
Well-Known Member
I’ve never seen anything like it, looks like it’s filled with large grain sand!
What is this fuse?
- Thread starter Rivers & creeks
- Start date
david_bagshaw
Well-Known Member
I believe the grains stop it popping too soon.
PaulRainbow
Well-Known Member
Looks like silica. In there to stop arcing when the fuse blows, some used sand, more modern versions would be ceramic.
What is it fitted to ?
What is it fitted to ?
pvb
Well-Known Member
It's a sand-filled fuse, intended to give a time lag before it blows.
jamie N
Well-Known Member
Often called a 'Slow Blow' fuse.
Rivers & creeks
Well-Known Member
Thank you. So to carry a spare I search for the same rating and specify slow blow? (As the actor said to the marine electrician)
TernVI
Well-Known Member
There should be some letters with the amp rating.
It's possible the fuse was just what was handy on the day, so ideally fit what the equipment specifies.
trbt
Active Member
A sand filled fuse is often fitted when there is a potential for very high fault currents. The purpuse of the sand is to cool and stop the arc as quickly as possible when the fuse blows and to absorb the energy from the rupture. Modern types are usually enclosed in ceramic and not glass.
Although the sand also slows down the fuse a bit, it is not the same thing as a slow blow fuse.
The best advice is to see what the equipment specifies (does it mention 'HRC' anywhere?). If there is special requirement for the type of fuse, it's usually marked accordingly on the device itself near the fuse holder.
Although the sand also slows down the fuse a bit, it is not the same thing as a slow blow fuse.
The best advice is to see what the equipment specifies (does it mention 'HRC' anywhere?). If there is special requirement for the type of fuse, it's usually marked accordingly on the device itself near the fuse holder.
PaulRainbow
Well-Known Member
What i said i post 3.
I also asked what it was fitted to, as it's rather unlikely to be needed on a modern boat.
trbt
Active Member
Yes you did, sort of. The thread did veer off to the 'slow blow' path right after that so I felt a little elaboration wouldn't hurt.
Putting a regular slow blow fuse where a HRC fuse is required would not be a good idea.
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PaulRainbow
Well-Known Member
Absoluely
I agree, but i'm struggling to think of an application for a HRC fuse on the typical motor sailor that the OP owns. Hopefully he'll pop back and tell us where the fuse was fitted.
Rivers & creeks
Well-Known Member
Sorry for the late reply. It’s in the power supply box for a Simrad RADAR/plotter so I guess it’s likely to have bursts of high current? I don’t carry anything on board that’s like it so I need to source spares and “sand filled fuse” won’t help a google search ?
Tzu
Well-Known Member
I'm probably not the only one to have just tried googling that out of curiosity.. google images shows a number of them so one of them at least must be a suppliers picture.
jamie N
Well-Known Member
On 'older' designs of ROV, many of the fuses in motor control circuits were 'FF': very fast acting, and were prone to go at a very inconvenient time. Almost always they were changed out for 'TT': very slow acting, which led to far greater reliability. The items were designed for running with the 'clean' onshore supply, rather than the (often) very spiky offshore supply.
Alex_Blackwood
Well-Known Member
It is a HRC (High Rupturing Capacity ) Fuse. That is what you want to look for. Try Dr. Google for explanation of HRC.
PaulRainbow
Well-Known Member
There is no need for a HRC fuse in your plotter or radar installation. It's normal to have separate fuses for the plotter and radar. Look up the fuse ratings in the manuals and fit standard fuses. I'd be inclined to ditch inline glass fuses and fit new blade fuses.
trbt
Active Member
I was wondering if it might have come out of a multimeter accidentally left on "amps" mode when testing voltages
That's often how people get introduced to all sorts of "weird" fuses..
