disconnect fused or non fuse

[aone]

Should I use a fused or a non fused disconnect for a mini split condenser.

Fujitsu AOU18RXLFZH

OUTDOOR UNIT : 36 type
Power source
208/230 V ~ 60 Hz

I am looking at this one,

https://www.amazon.com/dp/B000LF42NK/?tag=atomicindus08-20.

Thanks.

 

[plain garage]

I would go fused just so you can be positive when disconnecting electricity. You don't want someone flipping on the breaker when you're servicing the unit outside.

 

[Richard Cranium]

agreed I would want the fused also

 

[brewchief]

I would use a fused if the unit calls for a breaker or fuse that is not standard, if it just needs a 20 or 30 amp circuit then an unfused would be just fine, 25 amp breaker might be tougher to find and it may be easier to use a fused disconnect.

Sent from my XT1254 using Tapatalk

 

[PoorOwner]

I don't think the fused make a difference in servicing. It just needs to be in sight of the equipment and down stream of the breaker. Flipping the breaker won't do anything since you disconnected both legs of 240v at the disconnect. As close to the equipment as possible.

 

[manwithtools]

If the supplying circuit over current protective device is sized properly then there is no need for a fused disconnect. Either style "disconnects", the fused version costs more and serves no extra benefit.

 

[joe_padavano]

if the supplying circuit over current protective device is sized properly then there is no need for a fused disconnect. Either style "disconnects", the fused version costs more and serves no extra benefit.

^^^this!

 

[justinjoyal]

If the supplying circuit over current protective device is sized properly then there is no need for a fused disconnect. Either style "disconnects", the fused version costs more and serves no extra benefit.

Exactly. A regular disconnect is what you need if there is a proper circuit breaker installed in your electrical panel.

 

[Git]

Non Fused Disconnect

When eComfort sold me my Mr Slim, one of their recommended accessories was this disconnect with the whip

Bramec 60A Non-Fused Metal Disconnect Box + 4' Electrical Whip (10 GA) Kit
http://www.ecomfort.com/Bramec-NFDWHIP/p55821.html

You can get a Non-Fused Metal Disconnect Box from Home Depot for $5
http://www.homedepot.com/p/GE-60-Amp-240-Volt-Non-Fuse-Metallic-AC-Disconnect-TFN60RCP/100674085

 

[zmaxmotorsports]

I would go fused just so you can be positive when disconnecting electricity. You don't want someone flipping on the breaker when you're servicing the unit outside.

Do you guys know the differance between a fused/non fused disconnect?

 

[bonneyman]

I always preferred having a fused component somewhere in the system. Circuit breakers aren't foolproof.

 

[Jackfre]

I just cleaned a friends Fujitsu's, a Tri and a single. I pulled the fused disconnect on each system and put it in the glove compartment. He asked what I was doing and I told him I was a chicken. I can't say fused or not technically and agreed that the breaker should be sufficient. That said, as to electricity, I'm kind of a belt and suspenders kinda guy...or a chicken.

 

[nick2010tundra]

The disconnect outside is for the service tech to disconnect power for servicing, You should have the fuse inside at the feed. Having 2 Fuses on it will only cause issues and cost

 

[justinjoyal]

I would go fused just so you can be positive when disconnecting electricity. You don't want someone flipping on the breaker when you're servicing the unit outside.

There is a breaker in the main panel.

The outside disconnect is (usually) like a handle that you pull out so the circuit is completetly cut off.

Outside by the unit you put the disconnect the service tech will use to

I always preferred having a fused component somewhere in the system. Circuit breakers aren't foolproof.

There is always a fuse or breaker plus the outside disconnect.

 

[LS6 Tommy]

If the supplying circuit over current protective device is sized properly then there is no need for a fused disconnect. Either style "disconnects", the fused version costs more and serves no extra benefit.

^^^this!

Exactly. A regular disconnect is what you need if there is a proper circuit breaker installed in your electrical panel.

Code requires the equipment to be installed according to the manufacturere's instructions. The requirement for a fused disconnect is dictated by the manufacturer. If the equipment data plate states "use a maximum overcurrent device rated at ** amps" you do not need a fused disconnect. If it says "maximum fuse size ** amps" there needs to be fuses somewhere in the circuit between the breaker and the unit and a fused disconnect is the easiest way to accomplish it. If it says something like "maximum breaker or fuse size ** amps" you have the option of going with breakers or fuses.

Tommy

 

[manwithtools]

Code requires the equipment to be installed according to the manufacturere's instructions. The requirement for a fused disconnect is dictated by the manufacturer. If the equipment data plate states "use a maximum overcurrent device rated at ** amps" you do not need a fused disconnect. If it says "maximum fuse size ** amps" there needs to be fuses somewhere in the circuit between the breaker and the unit and a fused disconnect is the easiest way to accomplish it. If it says something like "maximum breaker or fuse size ** amps" you have the option of going with breakers or fuses.

Tommy

Tommy,
Great point and it's been so long since I encountered an appliance that was fuse only on the name plate I did not even consider that in my reply. The fact that the unit is a Fujitsu and primarily marketed in Asia (where fuses are more commonly used still) it's possible that it does say "Max Fuse Size".

I just looked that model up on their web site and it seems to indicate Max Fuse size (although one document said 20 amps and another said 30 amps).

I would like to see a picture of the units physical name plate to see how it's actually worded on it.

If it says "Max Fuse Size" only then Tommy is right, it would need a fused disconnect despite what I said in my earlier post.

OP, you still need the proper circuit breaker protecting this circuit and the proper wire size as well.

 

[Bacon!]

One benefit to fused is that an ignorant homeowner won't have a problem, see a tripped breaker and flip it back on before repairing the problem, risking fire or more damage. They probably won't have spare fuses. Sure they could just go buy fuses but this gives them more time to think about what they're doing.

 

[Git]

One benefit to fused is that an ignorant homeowner won't have a problem, see a tripped breaker and flip it back on before repairing the problem, risking fire or more damage. They probably won't have spare fuses. Sure they could just go buy fuses but this gives them more time to think about what they're doing.

Except the the person asking the question is installing his own MiniSplit - so I don't know if you would consider him an "ignorant homeowner", but I wouldn't...

Why make things difficult. You have a circuit breaker right? Then you just need a simple non-fused disconnect. ITS A DISCONNECT

 

[Fixin'Stuff]

I would go fused just so you can be positive when disconnecting electricity. You don't want someone flipping on the breaker when you're servicing the unit outside.

The whole point of even having the outside disconnect is to do just that, DISCONNECT the power from the controlled device. I don't even turn off the breaker when I'm working on an a/c unit, because the disconnect jumper is in my pocket. Thus there is zero voltage on the wires between the disconnect and the load. Play with the breaker at the panel all you want. It won't make any difference at all at the unit.

 

[aone]

I will have a 20 amp double breaker run with #10-3 BX wires. I will get a 60A Non-Fused Metal Disconnect from Homedepot as in the link posted above. I have the manual but could not attached it due to its size. It is the type 18. It does not mention the fuses. Thanks for all the replies.

 

[mikebaker1129]

The whole point of even having the outside disconnect is to do just that, DISCONNECT the power from the controlled device. I don't even turn off the breaker when I'm working on an a/c unit, because the disconnect jumper is in my pocket. Thus there is zero voltage on the wires between the disconnect and the load. Play with the breaker at the panel all you want. It won't make any difference at all at the unit.

^ is the answer.
If you uses fuses and have an issue,the service tech may not have the fuses your unit uses on the truck. Say a condenser fan motor goes to ground and blows 1 or both fuses ,tech replaces the fan but does not have the fuses. Your unit is still down.
A properly sized circuit breaker makes the fused disconnect redundant.

 

[justinjoyal]

I will have a 20 amp double breaker run with #10-3 BX wires. I will get a 60A Non-Fused Metal Disconnect from Homedepot as in the link posted above. I have the manual but could not attached it due to its size. It is the type 18. It does not mention the fuses. Thanks for all the replies.

Why 10/3 ? 12/2 is just fine.

 

[aone]

Why 10/3 ? 12/2 is just fine.

You are right 12/2 will be fine. I am running 3 wires in case later another circuit comes in need. #10 because the run will be at least 50ft. Do you think I should stick with #12 and the run length does not matter?

 

[justinjoyal]

Lenght matters but 50 ft is nothing to worry about.

 

[aone]

You just save me some bucks because I will go with 12/2 instead. There is a box to the upper floor. I can always pull another wire. Thanks for your input.

 

[zmaxmotorsports]

^ is the answer.
If you uses fuses and have an issue,the service tech may not have the fuses your unit uses on the truck. Say a condenser fan motor goes to ground and blows 1 or both fuses ,tech replaces the fan but does not have the fuses. Your unit is still down.
A properly sized circuit breaker makes the fused disconnect redundant.

 

[rburke65]

A disconnect is a "non fused" switch. Use a disconnect with a breaker at the source.

 

[zmaxmotorsports]

Tommy,
Great point and it's been so long since I encountered an appliance that was fuse only on the name plate I did not even consider that in my reply. The fact that the unit is a Fujitsu and primarily marketed in Asia (where fuses are more commonly used still) it's possible that it does say "Max Fuse Size".

I just looked that model up on their web site and it seems to indicate Max Fuse size (although one document said 20 amps and another said 30 amps).

I would like to see a picture of the units physical name plate to see how it's actually worded on it.

If it says "Max Fuse Size" only then Tommy is right, it would need a fused disconnect despite what I said in my earlier post.

OP, you still need the proper circuit breaker protecting this circuit and the proper wire size as well.

I've never seen an inspector say a fused disconnect was required.
I'd say the max fuse size is a universal way of saying maximum circuit protection,there are still lots of older houses around here that have fused service panels.
A fused disconnect is just one more thing to go wrong in the middle of the night.
Hell most younger service guys have never seen a cartridge fuse,let alone keep them on their service truck.
I've learned over the years to save all the good fuses and cartridge fuses anytime I change out an old fused service panel,you never know when you're going to need one in the middle of the night.