# Size (temperature) of a Thermal fuse for a shop vac motor

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#### Bill Kinley

##### New Member
My shop vac stopped working and I diagnosed the problem to be a blown thermal fuse. I have checked with the manufacturer and other sources and haven't come up with the size to replace it.

Personally I don't have a clue, but I suspect it is less than 100 degrees Celsius. Does anyone know or have any suggestions?

Thanks,
Bill

#### gerty

##### Member
There should be a part# or temp marked on it.

#### Bill Kinley

##### New Member
It has no markings, actually it is a piece of metal (wire) between two electrical connections. I am assuming it is a thermal fuse, can't imagine what else it could be, anyway it interrupts the circuit not allowing it to work..

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#### jchistia

##### New Member
Thermal Fuse Device in Shop Vac

I also have found discarded shop vacs with this device non-operational. My guess is that these "fuses" are included in the design because of product liability concerns. If the motor were to catch fire and consume the plastic, noxious fumes along with the possibility of fire would occur. These fuses are what I call "fail soft" devices. Unfortunately, they are not fail-soft as far as the utility of the vacuum goes. It doesn't make any difference if your vacuum is dead because the motor burned up or the fuse melted. The vacuum is considered junk either way. Too costly to take it to a repair shop. Very few of us attempt repairs and when we do, we cannot find parts. I found a similar fuse INSIDE of a condensor motor case on a Maytag rollaround portable A/C unit. The unit had to be nearly entirely disassembled to get to the fuse. The biggest challenge was to find suitable crinmp connectors as soldering is near impossible. Cost? $1.37 or the part. New unit?$600. By the way, I suspect that the "link" material in the shop vacs is no more than a length of solder. Melting points of different solders can be found at RF Cafe - Solder Properties Melting Point After fooling around with my found vacuum, I ended up bypassing the device. My 30 year old Sears Craftsman doesn't have one and is still running.

#### romueller

##### New Member
same thing for me

Just diagnosed the exact same thing on my ShopVac 90L500A. Blown fuse for which I can't find any specs. Just a piece of metal material between two contacts in an unmarked plastic holder. $100 vacuum tanked by a$0.001 piece of metal. I swear it almost looks like it was meant to wear out after a certain number of motor starts. I don't think I'll be buying ShopVac brand again. Argghhhh!

#### jchistia

##### New Member
Shop Vac "fuse" -- warranty item if < 5 years

#### alanis

##### New Member
Thanks for the info Bill!

My husband wanted to wire it directly and use it then unplug when we are done.

How long has yours lasted since you changed the fuse?

#### Bill Kinley

##### New Member
I fixed it maybe three months ago, but only use it in the garage. I expect it to last a long time.

#### RD Gibb

##### New Member
Resetable Thermal cutoff

I had this same problem occur with my shop-vac. Fortunately I happened to have an old eureka vacuum cleaner with a bad cord that I didn't have the heart to throw away. I tore it apart and found the thermal cutoff screwed to the motor housing. I am not sure what the rating is on the eureka cutoff but after cutting the heat-shrink tubing off of it (to eliminate any insulation for the thermal switch) and placing it in approximately the same position as the original in my shop-vac it works great. I have not had it kick off yet and even if it does I can just let it cool down and it will reset. Hope this helps.

#### KMoffett

##### Well-Known Member
even if it does I can just let it cool down and it will reset. Hope this helps.
All of the "thermal fuses" I've ever encountered are not "self resetting". They act like a normal fuse and open permanently. That's the maddening thing about them, because there are no readly available exact replacements like normal over-current fuses.

Looking for a replacement for my daughter's PIZZAZZ pizza baker. I can find them but: one on eBay for $11+shipping, or 10 (minimum order) from the fuse manufacturer for$26 with shipping.

Ken

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#### KMoffett

##### Well-Known Member
Now that looks do-able. Thanks! I'll bookmark that resource.

ken

#### RD Gibb

##### New Member
Check out the thermal protection used in most modern household vacuum cleaners. According to the instructions supplied with said vacuums if the motor overheats the fuse will kill the motor. If this happens simply allow the motor time to cool while you clean the filters or change the bag to ensure proper airflow the fuse will reset and you are off to the races.

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