10/3 to A/C disconnect

[jmiller_2308]

When I roughed in I ran 10/3 + ground from the panel to where I plan to install a 60 amp disconnect. The breaker is a double 30 amp breaker that I plan to use the black and red wires for the hot, the copper will go to ground, but I'm not sure what to do with the white.

I've been reading that I should not use the white and that I should just put a wire nut on it in the disconnect box. If so, would I do the same in the panel or should I cut the white wire off at the panel?

Before reading the above advice I thought I should hook the white wire to the neutral bus in the panel and connect the white wire to the ground terminals in the disconnect. The disconnect box also has a separate green grounding wire that I would connect the copper to.

Any suggestions?

 

[Norcal]

When I roughed in I ran 10/3 + ground from the panel to where I plan to install a 60 amp disconnect. The breaker is a double 30 amp breaker that I plan to use the black and red wires for the hot, the copper will go to ground, but I'm not sure what to do with the white.

I've been reading that I should not use the white and that I should just put a wire nut on it in the disconnect box. If so, would I do the same in the panel or should I cut the white wire off at the panel?

Before reading the above advice I thought I should hook the white wire to the neutral bus in the panel and connect the white wire to the ground terminals in the disconnect. The disconnect box also has a separate green grounding wire that I would connect the copper to.

Any suggestions?

You wasted your money with 10/3, 10/2 is all that is needed. The part in bold should never be done, grounding conductors, and grounded (neutral) conductors are bonded together just once at the service, after that they must be separate, keep it simple & just wire nut the unused/ unneeded neutral & tuck it out of the way.

 

[jmiller_2308]

Thanks for confirming what I've been reading elsewhere.

 

[Stuart in MN]

When I roughed in I ran 10/3 + ground from the panel to where I plan to install a 60 amp disconnect. The breaker is a double 30 amp breaker that I plan to use the black and red wires for the hot, the copper will go to ground, but I'm not sure what to do with the white.

Is there a reason for using a 60 amp disconnect on a 30 amp circuit? It will work if you already have it on hand, but a 30 amp disconnect is all that's needed.

 

[brewchief]

Is there a reason for using a 60 amp disconnect on a 30 amp circuit? It will work if you already have it on hand, but a 30 amp disconnect is all that's needed.

I'm thinking he is using an unfused disconnect, I've never seen an unfused 30. If using a fused disconnect the size break in fuses is between 30 and 35 so the smallest fuse that will fit a 60 is a 35, there are adapters to use the smaller fuses in the large sized fuse holders but i try to avoid them.

 

[AndyCBR]

When I roughed in I ran 10/3 + ground from the panel to where I plan to install a 60 amp disconnect. The breaker is a double 30 amp breaker that I plan to use the black and red wires for the hot, the copper will go to ground, but I'm not sure what to do with the white.

I've been reading that I should not use the white and that I should just put a wire nut on it in the disconnect box. If so, would I do the same in the panel or should I cut the white wire off at the panel?

Before reading the above advice I thought I should hook the white wire to the neutral bus in the panel and connect the white wire to the ground terminals in the disconnect. The disconnect box also has a separate green grounding wire that I would connect the copper to.

Any suggestions?

Running the 10/3 with ground is not necessarily a bad idea. You have the option to run an appliance that requires a 4 wire hookup should you need it in the future.

Just cap off the white wire in the disconnect. Hook it up to the neutral bar in the panel just like all the other neutrals.

Do not hook it to the ground buss. Once you leave the main service, ground and neutral are separate and should remain so.

 

[pattenp]

The 60A AC nonfused disconnect is just a switch that's rated up to 60A and 10HP. They can be found at Lowe's or HD and are relatively cheap. You can get a 30A safety switch but they cost a lot more.

 

[Norcal]

Running the 10/3 with ground is not necessarily a bad idea. You have the option to run an appliance that requires a 4 wire hookup should you need it in the future.

Just cap off the white wire in the disconnect. Hook it up to the neutral bar in the panel just like all the other neutrals.

Do not hook it to the ground buss. Once you leave the main service, ground and neutral are separate and should remain so.

The need for a neutral at a 240V A/C unit is nil, but since the deed is done it does not matter.

 

[jmiller_2308]

Running the 10/3 with ground is not necessarily a bad idea. You have the option to run an appliance that requires a 4 wire hookup should you need it in the future.

Just cap off the white wire in the disconnect. Hook it up to the neutral bar in the panel just like all the other neutrals.

Do not hook it to the ground buss. Once you leave the main service, ground and neutral are separate and should remain so.

Thanks. Connecting the white to the neutral in the panel and capping at the disconnect is the full answer i was looking for.

 

[jmiller_2308]

Is there a reason for using a 60 amp disconnect on a 30 amp circuit? It will work if you already have it on hand, but a 30 amp disconnect is all that's needed.

It is a 240 volt circuit made from 2 120 legs each of which is 30 amps so a 60 amp disconnect is appropriate. 60 amps is necessary for the A/C condenser. And yes, the 2 breakers are connected.

 

[pattenp]

It is a 240 volt circuit made from 2 120 legs each of which is 30 amps so a 60 amp disconnect is appropriate. 60 amps is necessary for the A/C condenser. And yes, the 2 breakers are connected.

No... that is still a 30A circuit, not 60A. The two 120V legs are 180 deg from each other so you just have 30A at 240V.