I am installing a Mitsubishi mini-split with an indoor and an outdoor unit (MUZ-A15NA). I ran 220V wire from the electrical box outside. It is on a 15 amp breaker as the instructions have it rated as 15 amp max. I purchased a disconnect switch for the outdoor unit that is a 60 amp fuseable switch (cartridge fuses). I know this is much higher then 15 amp but I was figuring on buying 15 amp cartridge fuses to install.
My question is, will this be work or should I try to find a disconnect switch rated at 15 amp? In addition I've noticed that the 15 amp cartridge fuses are much smaller than the fuse holders in the disconnect switch, which I think will be a problem. The 60 amp switch was the lowest rated switch I was able to find (Lowe's, Home Depot).

Thanks.

Find a disconnect rated 30 amps, 15 amp cartridge fuses will fit without need of fuse reducers if 60 amp is used. Be sure to use Time Delay fuses.

So they have fuse reducers so a 15 amp fuse will fit in the 60 amp switch?
I'll check around for a 30 amp disconnect.
Thanks.

Yes, but I don't recommend then unless absolutely necessary, they usually loosen.

Quote:

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Originally Posted by Droff

I am installing a Mitsubishi mini-split with an indoor and an outdoor unit (MUZ-A15NA). I ran 220V wire from the electrical box outside. It is on a 15 amp breaker as the instructions have it rated as 15 amp max. I purchased a disconnect switch for the outdoor unit that is a 60 amp fuseable switch (cartridge fuses). I know this is much higher then 15 amp but I was figuring on buying 15 amp cartridge fuses to install.
My question is, will this be work or should I try to find a disconnect switch rated at 15 amp? In addition I've noticed that the 15 amp cartridge fuses are much smaller than the fuse holders in the disconnect switch, which I think will be a problem. The 60 amp switch was the lowest rated switch I was able to find (Lowe's, Home Depot).

Thanks.

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I finally got around to getting a 30 amp box and I'm planning on getting it wired now. I bought a 220V box but it looks like I don't have enough connections. I have the line in which is at the fuses (red and black) and then the ground. It doesn't look like I have a separate connection for the neutral. Is the neutral and the ground tied together in the box or just not connected?
Thanks.

Just wirenut the neutrals, or an isolated neutral bar.
60 Amp disconnect was fine, the wires are protected by the 15 amp breaker.

No, do not connect the equipment ground and the neutrals together, as Strat states, just wirenut the two neutrals together.

Be sure the equipment grounds do connect to the metal can of the disconnect, can be either with a ground bar or wirenuts and a pigtail to a green machine screw driven directly into a threaded hole of the disconnect.

Strat, sure the 60 amp switch would have been protected by the 15 amp breaker, but the Droff would have needed to use fuse reducers to install 15 amp fuses in the 60 amp switch, more possible loose connections. Seems to be a moot point, since Droff was able to find a 30 amp fusible switch that does accept 15 amp fuses with no reducers needed, plus saved some money not buying something not needed.

Couldn't he have used the 60 amp fuses he had, he said he had the 60 amp disconnect already. Sounds like he's all set. Could he have used it, being a means of Disconnect?
Take Care

No I don't think so, the specs on Mitsubishi require fuse protection, of a specific size rating, and the 60 amp fuses would be too large. Even thou the breaker is most likely HACR rated, and can take the place of fuse, this manufacturer insists on fuses. I run into this for every Mitsubishi unit I wire.

Thanks. Don't have their specs. Thought maybe it was disconnect he already had, and wanted 15 amp fuses, because it was what it accepted. And 15 Amps was protection requirement. Sounds like he may have it.

Thanks for the input guys.

The ongoing saga of my mini split continues. I mistakenly did not run any line voltage to the indoor unit for the fan and it calls for 220V. I purchased a 25' box of 14 ga 14/3 wire and fished it to where I need it. The problem is that I'm about 3' too short. I have plenty of 14/3, just not all in one length. Can I splice this in a junction box to give me the length I need? I know it may not be optimal, but does it present a problem? The unit is fused at 15 amps.
Thanks.

Sure you can use junction box, or Bell box. Be sure it is grounded.