Fuse bar

[Dietrichfarms]

How do I figure out what amp rating theses bars are. There are no markings on them.
They are on the house battery 12 and 24 volt leads going to the inverter.

[ArtGill]

Could it be a shunt for an amp meter?

[Dietrichfarms]

Don't think they are a shunt they are inline with the power coming from batteries to inverter. Found one in box of odds and ins when got bus that was melted off on one end. Feel like they are to be like a fusable link some how just can't figure out how many amps they would be. Would like to replace with a circuit breaker.

[TedCalvert]

Pretty sure they are ammeter shunts.  If it is inline to the inverter, it would be to read current to and from inverter.  Look for markings on them and post pic of same.

[scanzel]

The first picture has some wording under the metal strip you may need to remove one and seethe info on the plastic. I hope you are redoing the cable ends they look pretty bad, cracked and burned.

[Rick 74 MC-8]

Definitely Shunts. I have the same on my bus




Rick

[luvrbus]

? aren't shunts usually on the ground and fuseable links on the positive side

[Dietrichfarms]

They are on the positive 12 and 24 leads going to the inverter. Haven't gotten to get in compartment and remove to check for markings. The one loose one I have in hand does not have any markings on it, like I said really just want to figure out amp rating so can replace with circuit breaker.

[luvrbus]

I am probably out of my safe zone but that looks like a old style ANN current limiter

[gumpy]

How big do you suppose the flames were that burned those wire ends? 

If this were my bus, I'd be doing some serious electrical rework... or increasing my comprehensive insurance coverage.

I don't think they are fuses or shunts. They probably are current limiters to the inverter.

You need to figure out what your inverter requires for current limiting, not what these are, and then get bolt down or Class T type fuse to put on it.
Something like this:  http://www.waytekwire.com/item/46270/HIGH-AMP-FUSE-100-AMP/

Start with the size of the wire going to the inverter, and the wattage of the inverter. From that, you can figure out what you need.

[junkman42]

Meter shunt, meter is placed across the two small screws.  Most likely 50mv shunt.  Usually somewhere it will have markings such as 250a50mv.  At 250 amps across the shunt will read 50Mv.  could 25 or 10 mv shunt etc.  Not expert as "expert= drip under great pressure" .  John L

[stevet903]

Looks like a Stewart Warner ammeter shunt -

http://www.stewartwarner.com/en-US/Products/StewartWarner/Product-groups/Accessories/Shunt-for-Ammeters.aspx

[luvrbus]

Why a shunt on the house batteries and inverter leads ? that is big wiring for a shunt and amp meter

[Iceni John]

Sea Walsh's advice is to have Class T fuses as catastrophe fuses on the batteries' negative leads, and you should follow your inverter manufacturer's advice on what size of load fuse is needed for the inverter itself.   I will be using 300A Class T fuses for each battery bank and ANL fuses for each inverter, 300A for the Magnum MS2000 and something less for the eventual smaller second inverter.   The best prices for fuse holders and pass-throughs is from VTE Warehouse  -  they make several companies' parts, but its cheapest to buy "factory-direct": https://www.vtewarehouse.com/content/electromech/fuse/html/classt/classt.php    Class T fuses are fast-blowing, what you want for catastrophe protection, but ANL are slower-acting, better for short-term surges to the inverters.

Those crimps are scary.   Get the lugs crimped on with a good circumferential crimper such as a FTZ 94284, use tin-plated lugs near the batteries to resist the inevitable corrosion there from the batteries' fumes, use adhesive heat-shrink on those cables, then you should be good.   Don't use those hammer crimpers  -  they simply cannot make a "gas-tight" cold-welded fusion between the lug and cable strands.   It's also a good idea to check all your cables' and lugs' temperatures under load with an IR thermometer  -  any bad connections or under-sized cables will show up as warm or hot (not good).

Good luck, John

[gumpy]

Looks like a Stewart Warner ammeter shunt -

http://www.stewartwarner.com/en-US/Products/StewartWarner/Product-groups/Accessories/Shunt-for-Ammeters.aspx

Well, there you go. They seem to be shunts. I didn't see the screws on top that was pointed out by another poster, but this last link certainly seems to clear it up.

Doesn't answer why there's a shunt on the inverter positive feed, though.  I think normally they go on the negative return to the batteries. At least that's the way
the one on my Trimetric meter is set up.