Mystery fuses

[Proteus]

I have 2 fuses in my Salem 28 that I can't identify.

One is marked "ST" and the other "DSI" (which is oddly the same as one of the breakers in the breaker panel.

Can I get a translation, please?

[dimurrrw]

Just a wild guess but the DSI breaker may be for the electric heating element in the water heater. That would leave the 3 amp fuse for the spark ignitor (when running on gas) and the circuit board. The ST might be for the slide, if you have one.

[TURBS]

X2 on the dsi.
st =stereo?

[Proteus]

Originally Posted by f1100turbo

X2 on the dsi.
st =stereo?

My "stereo" is just a 12 vdc analog am/fm radio. I would hardly expect it to need a 15A fuse.

[Coreyhunt]

DSI is direct spark ignition.

ST is stereo as far as I know. 15 amp in my camper

[TURBS]

Originally Posted by Proteus

My "stereo" is just a 12 vdc analog am/fm radio. I would hardly expect it to need a 15A fuse.

Mine is 15 amp as well.
Pull the fuse see if it still works

[fonzie]

DSI is Digital Spark Ignitor for furnace and ST for stabaliser jacks: this is my guess. This is all 12 volts

[rbarrieau]

one of the 15 amps in my salem is a spare..and one on top is marked wrong "REF" because it runs the stand alone blower delay relay in the furnace.

[dimurrrw]

I wonder if the monitor is powered off of the "stereo"?

[Proteus]

Originally Posted by fonzie

DSI is Digital Spark Ignitor for furnace and ST for stabaliser jacks: this is my guess. This is all 12 volts

Stabilizers are all manual scissors jacks.

[Proteus]

Originally Posted by dimurrrw

I wonder if the monitor is powered off of the "stereo"?

What is the "monitor"?

[althebuilder]

If there is a line voltage circuit for the stereo system it would still likely have a 15 amp breaker on it, not because of the draw, but just because that is the most common breaker to put on a standard circuit. The capacity doesn't mean you have to use all of it.
The best way to find out what ST means is to turn it off and see what stops working or use a circuit tester to confirm. If you find out, make a note or label that is clearer to you so you will always know in an instant what circuits do what when you need that info.

[Proteus]

Does it matter that this is a fuse and not a breaker?

"...it would still likely have a 15 amp breaker on it, not because of the draw, but just because that is the most common breaker to put on a standard circuit. The capacity doesn't mean you have to use all of it."

Yes, it does. The radio is purely 12 volt. It will operate correctly if the 120 VAC power is unplugged so I seriously doubt that a fuse for it would be in the 120 VAC fuse panel.

And I do know that good circuit design requires that the fuse/breaker be the weakest link in the circuit and that it be the able to carry less load than the circuit it protects. A circuit always uses the lightest breaker/fuse that will allow the load to operate correctly. A simple radio may draw 5 amps. Over-fusing a circuit causes fires.

[dimurrrw]

Originally Posted by Proteus

What is the "monitor"?

It is basically the same thing as a PC monitor. Take all of the guts (amplifier, tuner, speakers) out of a TV and put them in the Multimedia (Entertainment) Center, along with an AM/FM tuner, CD/DVD player, antenna inputs, cable inputs, speaker outputs, etc, etc. Everything is now contained in the Multimedia/Entertainment Center, with the exception of the monitor (TV screen) and the speakers. Note that not all RV systems work this way.
So, what I was pointing out (a bit tongue-in- cheek,) was that the whole entertainment system might be powered off of that mystery 15 amp DC circuit. Assuming, of course, that ST stands for stereo and not something else. (Frankly, it would have made more sense to label the fuse ENT if that were the case.)

BTW I do believe that the fuses are on the converter and, thus, those circuits are all 12 volt. General rule of thumb for an RV: Breakers are used for 120 volts AC, fuses for 12 volt DC. Moral - keep a supply of fuses in the RV.

[Proteus]

Thanks...

I guess the next time I get up there, I'll have to pull that fuse and see if anything dies. I don't have an entertainment system; no stereo, no TV or DVD stuff, no CD player... nothing but an AM/FM radio and 4 little ceiling speakers. If pulling that fuse DOES kill the radio I'll definitely change from a 15A to a 3A. 15A is way too big for a little 12VDC radio.

[TURBS]

I would sure like to know what st is ..... let us know .
we are on the edge of our seats

[dimurrrw]

Originally Posted by f1100turbo

I would sure like to know what st is ..... let us know .
we are on the edge of our seats

Me too!

[The_Stuff]

most car stereos are the red 10A fuse.

[althebuilder]

Originally Posted by Proteus

Does it matter that this is a fuse and not a breaker?

Yes, it does. The radio is purely 12 volt. It will operate correctly if the 120 VAC power is unplugged so I seriously doubt that a fuse for it would be in the 120 VAC fuse panel.

And I do know that good circuit design requires that the fuse/breaker be the weakest link in the circuit and that it be the able to carry less load than the circuit it protects. A circuit always uses the lightest breaker/fuse that will allow the load to operate correctly. A simple radio may draw 5 amps. Over-fusing a circuit causes fires.

I apologize If I'm splitting hairs but I want to clarify my position and points I made earlier.

I agree that if it is an automotive style fuse it is the DC system.

I also agree that putting the wrong breaker or fuse on a circuit can lead to dangerous conditions that could cause a fire, I disagree though that putting a load of less than 15A on a circuit with adequate size wire properly installed is not overkill on an AC system, Most basic plugs in a house are 15 amp breakers where I live, but there is no need to to take them out and put in a smaller one if you are only running one light fixture on it and not maxing out the circuit. It doesn't cause a fire with a smaller load or even no load. This is why I think a standard 15Amp breaker could still be providing line voltage to an entertainment system, I'd bet most people have their radio at home plugged into a 15amp circuit, maybe even at the same time a tv, dvd, amp computer etc etc. But you won't have a fire if you unplug all but the stereo.

[Proteus]

Well, it turns out that the 15A "ST" fuse does, in fact, protect the radio.

Now, can somebody explain what the two RED 40A fuses to the left of the other fuses are for?