Ask Experts Questions for FREE Help !
Ask
    Droff's Avatar
    Droff Posts: 38, Reputation: 1
    Junior Member
    		  
    #1

    Oct 8, 2007, 02:34 PM
    Mini-Split wiring
    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.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
    Uber Member
    		  
    #2

    Oct 8, 2007, 03:24 PM
    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.
    Droff's Avatar
    Droff Posts: 38, Reputation: 1
    Junior Member
    		  
    #3

    Oct 8, 2007, 03:35 PM
    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.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
    Uber Member
    		  
    #4

    Oct 8, 2007, 03:39 PM
    Yes, but I don't recommend then unless absolutely necessary, they usually loosen.
    Droff's Avatar
    Droff Posts: 38, Reputation: 1
    Junior Member
    		  
    #5

    Oct 28, 2007, 08:53 AM
    Quote 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.
    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.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
    Uber Member
    		  
    #6

    Oct 28, 2007, 09:33 AM
    Just wirenut the neutrals, or an isolated neutral bar.
    60 Amp disconnect was fine, the wires are protected by the 15 amp breaker.
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
    Uber Member
    		  
    #7

    Oct 28, 2007, 10:20 AM
    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.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
    Uber Member
    		  
    #8

    Oct 28, 2007, 12:42 PM
    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
    tkrussell's Avatar
    tkrussell Posts: 9,659, Reputation: 725
    Uber Member
    		  
    #9

    Oct 28, 2007, 12:46 PM
    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.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
    Uber Member
    		  
    #10

    Oct 28, 2007, 04:33 PM
    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.
    Droff's Avatar
    Droff Posts: 38, Reputation: 1
    Junior Member
    		  
    #11

    Oct 28, 2007, 06:49 PM
    Thanks for the input guys.
    Droff's Avatar
    Droff Posts: 38, Reputation: 1
    Junior Member
    		  
    #12

    Nov 11, 2007, 10:37 AM
    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.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
    Uber Member
    		  
    #13

    Nov 11, 2007, 01:25 PM
    Sure you can use junction box, or Bell box. Be sure it is grounded.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

I'm in a split. [ 3 Answers ]

I'm in a 5/6 split ad I want to be in a normal 6th grade class. I think I won't be iclude in anyway of the 6th grade stuff. Help, cause I fell like a 5th grader still. And I am going to for the rest for the year. Help!! :eek:

"Popping noise" coming from mini-split AC unit [ 1 Answers ]

We have an "AllStyle" brand mini-split AC in our bedroom. It's about 1.5 years old. It works fine, except about a month ago, it started "popping" and "cracking"--making it virtually impossible to get a good night's sleep! The sound is like that of plastic-on-plastic expanding or contracting...

Mini split Problems! Turns off [ 4 Answers ]

Hi, I have a couple of mini split ac's and am having some issues. One works fine for about 10-30 minutes and then just turns off. Fan stops but it puts out cold air when it runs. This one is a bondaire r22 unit. I have another 33,500 BTU dual zone mitsu mr slim 17+17. This unit doesn't cool...

Split up? [ 10 Answers ]

My partner and I split up approx 2 months ago after being together for 5 years, we have a 14 month old little boy together. One of the main reasons we splilt up was because he went out on weekends quite abit when we were together and didn't come home till early hours of the next morning, I use to...

New wiring of heatpump split system [ 2 Answers ]

My house trailer has only electric heat. I have added the "A" coil and heatpump. I have replacaed the two wire thermostate cable with a five wire cable. One goes from the thermostate to the furnace the other goes from furnace to the outside unit. I'm using the two heaters as the aux heat. I have...

View more questions Search