Microwave fuse

Go with the 15 Amp - just be sure that it's a fuse for a microwave and not the standard type of fuse. I believe CT sells some of them.

sonajatt wrote: ↑ Panasonic operating instructions guide says to use 20amp fuse.
Actual circuit board on microwave shows 18amp.
The wall receptacle is on 15amp.
And I pulled 15amp fuse from it.

Should I replace it with 15 or 20amp fuse?
Btw microwave won’t turn on.

You sure it's the microwave and not the outlet? If on a 15A outlet, the safe thing to do is have the MW on a 15A fuse, so it blows first.

I recall reading on Panasonic site the microwave is designed to run on 15amp circuit as it draws 16-17amp in beginning and that won't trip 15 amp breaker unless something else drawing power on that circuit. As megatron runs awhile it draws less, so its under 15amp and breaker doesn't heat up long enough to trip.

"Btw microwave won’t turn on"

Check the 2 door latches, if not aligned they blow that fuse and prevent microwave from running....the latches must interlock at exactly the same time. I'm not smart enough to know all this, tangled with same issue on my parents Panasonic MW a few years back and found info on an appliance repair site. Blew 2 ceramic fuses before finding the door lock issue causing it.

The 15A fuse, it's the microwave fuse? Do you have fuses or breakers in your house? Sounds like it should be on a dedicated 20A, even if it's only a 15A, still needs to be dedicated.

Zamboni wrote: ↑ I recall reading on Panasonic site the microwave is designed to run on 15amp circuit as it draws 16-17amp in beginning and that won't trip 15 amp breaker unless something else drawing power on that circuit. As megatron runs awhile it draws less, so its under 15amp and breaker doesn't heat up long enough to trip.

"Btw microwave won’t turn on"

Check the 2 door latches, if not aligned they blow that fuse and prevent microwave from running....the latches must interlock at exactly the same time. I'm not smart enough to know all this, tangled with same issue on my parents Panasonic MW a few years back and found info on an appliance repair site. Blew 2 ceramic fuses before finding the door lock issue causing it.

Yup, both of my Panasonics had no issues on a 15A fuse.

And the interlock is true, as GE has been out to my rental property 3 times this year to the GE microwave blow the dedicated breaker ... the last time they found the dock interlock switches were the issue and hasn't blown since.

Wall receptacle is in dedicated ‘over the oven’ microwave spot/box cut out.
I plugged a lamp into receptacle and turned off all 20amp breakers at panel; so definetly its a 15amp recpetacle. Not sure if it’s shared, not too concerned about it.
MW was working fine but all of sudden stopped, so my first attempt will be at changing the fuse.

sonajatt wrote: ↑ Wall receptacle is in dedicated ‘over the oven’ microwave spot/box cut out.
I plugged a lamp into receptacle and turned off all 20amp breakers at panel; so definetly its a 15amp recpetacle. Not sure if it’s shared, not too concerned about it.
MW was working fine but all of sudden stopped, so my first attempt will be at changing the fuse.

Did you check the fuse to see if it's actually toast?

craftsman wrote: ↑ Did you check the fuse to see if it's actually toast?

Yes I tried with multimeter (not an expert MM user) it does look toast.

sonajatt wrote: ↑ Yes I tried with multimeter (not an expert MM user) it does look toast.

Then it's probably the fuse more than anything else.

When I worked in retail consumer electronics in another life, we handled to shipment of microwaves under warranty back to the service depot for repair. The most common repair in microwaves that have no power was the fuse needed replacement... about 9 out of 10 times. The sad thing is how many microwaves end up in landfills because of a blown $2 fuse and no-one even attempts to repair it.

craftsman wrote: ↑ Then it's probably the fuse more than anything else.

When I worked in retail consumer electronics in another life, we handled to shipment of microwaves under warranty back to the service depot for repair. The most common repair in microwaves that have no power was the fuse needed replacement... about 9 out of 10 times. The sad thing is how many microwaves end up in landfills because of a blown $2 fuse and no-one even attempts to repair it.

Agree, repair costs are high and people don’t attempt to open appliances on their own. (Which is understandable)

So I should replace this with 15 or 20 amp fuse?

sonajatt wrote: ↑ So I should replace this with 15 or 20 amp fuse?

If you use a 15A fuse, then there is a 50-50 chance that the internal fuse will blow before the breaker will, and that will require you to open up the microwave more often.

I suggest you use a 20A fuse.Your breaker should offer protection against overloading the house wiring, and the fuse will be your backup in a case were the breaker fails to pop. Coincidentally that agrees with your owners manual. You may also want to use a slo-blow fuse so that the fuse doesn't blow on the momentary startup current.

I'm still not certain if the fuse protects the AC line into the microwave, or it could be protecting the DC power supply as it does in many electronic devices. If the breaker allows 110v * 15A, or 1650 Watts, and it powers a 12VDC power supply, then 1650W/12V , or 137A could flow from a well built built power supply. Perhaps they chose a fuse to limit the output of the power supply to 15A

sonajatt wrote: ↑ Agree, repair costs are high and people don’t attempt to open appliances on their own. (Which is understandable)

So I should replace this with 15 or 20 amp fuse?

I would go with what's been working - 15A. After all, how long have you had the microwave now? A few years at least, right? So, if a 15A has been good for that length of time, why won't be it good for a few more years UNLESS there's something else wrong with the microwave! In that case, you don't want to go with a 20A fuse just in case there is something wrong.

Put another 15 in it, if it snaps again in a while put the 18 amp the board calls for. If that blows you likely have an issue within the microwave. If the first one blows right away when you plug the microwave back in there is a problem.

Went with 20amp 120/240v; couldn’t find 15amp/125v -only at multiple small appliance stores.

craftsman wrote: ↑ Go with the 15 Amp - just be sure that it's a fuse for a microwave and not the standard type of fuse. I believe CT sells some of them.

sonajatt wrote: ↑ Went with 20amp 120/240v; couldn’t find 15amp/125v -only at multiple small appliance stores.

What he is referring to as a Microwave fuse is a "delayed blow " Rather than a regular ( quick blow ) Fuse.

Here's a link to Order some.

https://www.amazon.ca/Bussmann-BP-T-15- ... 000BQUM10/
https://www.amazon.ca/Leviton-7942-15-T ... B000FK9WSQ
You can also actually visit a local actual electrical supply store to get some.

Its Kinda Important that you use the correct Fuse and not just find whatever Fuse you happen to have Handy at the Local BigBox Hardware store.

Supahhh wrote: ↑ What he is referring to as a Microwave fuse is a "delayed blow " Rather than a regular ( quick blow ) Fuse.

Here's a link to Order some.

https://www.amazon.ca/Bussmann-BP-T-15- ... 000BQUM10/
https://www.amazon.ca/Leviton-7942-15-T ... B000FK9WSQ
You can also actually visit a local actual electrical supply store to get some.

Its Kinda Important that you use the correct Fuse and not just find whatever Fuse you happen to have Handy at the Local BigBox Hardware store.

A microwave fuse isn't a plug type screw in fuse like your links, its a ceramic cartridge fuse that looks like this:
https://www.canadiantire.ca/en/pdp/levi ... #store=460

Correct, above amazon fuse links are for older stoves etc.
Anyways, long story short (refer my first post for details), since I had 3 different reference point; I did some electrical calculations and 20amp fuse is what I decided to go with and is working like a champ.