difference in square d main panels

[srmofo]

Im getting ready to finally wire the garage. My house panel is a Square D homeline. Whats the difference between Homeline and QO? Is it worth the additional $50 for the box and almost twice the cost for breakers? Id like to keep everything the same to simplify things, and save a few bucks if theres no real benefit to the more expensive box.

Then the guy at the depot goes off and suggests CH, just to complicate things a little more for me. Am I just over thinking this?

While I've got you here, Ive got a compressor Im wiring 17.9 amps, 240 volts, supposedly 7 hp. approx 4300 watts. Do I need to recheck my math in assuming I only need 10/3 and a 30 amp breaker? or did I miss a step where you can only have X% of the rated circuit?

I'm a newb to this stuff but Im trying to learn and theres only one way I know. Ive got 2 sparky neighbors that will be overseeing me, but I find I learn alot better by doing not watching.

 

[sberry]

Keep it the same.

 

[Norcal]

Keep it the same.

No reason to mix up the panels, it's aways good to keep em the same.

 

[Torque1st]

While I've got you here, Ive got a compressor Im wiring 17.9 amps, 240 volts, supposedly 7 hp. approx 4300 watts. Do I need to recheck my math in assuming I only need 10/3 and a 30 amp breaker? or did I miss a step where you can only have X% of the rated circuit?

According to my tables the motor is ~3HP. The #10 wire is OK but you need a 35A or the next size up 40A breaker for the starting current.

Somebody can check that with the NEC. Motor circuits have their own special rules. I don't have access to the new NEC codes.

 

[rodm1]

No reason to mix up the panels, it's aways good to keep em the same.

QO has better panel options and build. But in your case I would stay with what you have.

 

[sberry]

Originally Posted by srmofo
While I've got you here, Ive got a compressor Im wiring 17.9 amps, 240 volts, supposedly 7 hp. approx 4300 watts. Do I need to recheck my math in assuming I only need 10/3 and a 30 amp breaker? or did I miss a step where you can only have X% of the rated circuit?

10/2 with ground and a 30A breaker.

 

[foolishpride]

The main difference between the QO and the Homeline is that the QO has copper bus in it, and the Homeline has aluminum bus in it.

 

[Torque1st]

I only have the 2002 NEC. Article 430 contains provisions for motors and motor controls. Larger branch circuit breakers are allowed for motor circuits. Check the 2005 or 2008 NEC as applicable in your community.

 

[sberry]

Yes they are allowed but really only if needed, you don't have to size up to the max. This is an area there will be very little in the way of code changes from year to year. About the only ones I can think of from the top of my head that effect guys here are the change allowing only 90A on a 2 alum sub feed, requiring 4 wires to detached structures and AFCI. May be others, I am sure someone can enlighten us. Biggest one they ever came up with that was night and day was when they adopt grounding and I believe that took 2, I see house built in 60 that only had 3 wire on kitchen and laundry.

 

[sberry]

I assume they make a few changes as wire coating technology improved but even appliance install codes have remained constant except for grounding changes. A couple issues with grounding change, now they ground to footer steel, don't allow using water pipes as grounding conductor from recepts, etc.

 

[Torque1st]

I have no idea if they have made changes in those sections. Most of my code books are old. The recommended size is 35A for a 3HP motor. He may be OK with the 30A but if it does not work out he will be buying another breaker. A compressor is considered a hard-start application.

I have one old outlet in my house that is grounded to a water pipe and the main panel is also grounded to the water pipe at the service entrance. I understand the ground changes since someone may replace a section of copper water pipe with plastic and destroy the ground connection. Both of those situations in my house (1962) will be addressed when the new SE panel is installed.

 

[sberry]

Yes, grounding the water pipe is required and so is using it as a ground electrode if its metal, common practice at one point was using metal piping as a grounding conductor for fault returns, as the 3rd wire is not allowed anymore.
I have a 3 hp comp, Dayton, runs from a 30A breaker, never had a trip. My pressure washer with 4 hp also has never tripped on a 30. Says its a 5 hp but the run current is 22A. Baldor motor. My well, 3 hp rated with run of 15A tripped after about 10 yrs and a couple yrs later tripped again on a 20, changed it out to a 30. Didnt want it to happen when I wasnt around.

 

[Norcal]

Yes they are allowed but really only if needed, you don't have to size up to the max. This is an area there will be very little in the way of code changes from year to year. About the only ones I can think of from the top of my head that effect guys here are the change allowing only 90A on a 2 alum sub feed, requiring 4 wires to detached structures and AFCI. May be others, I am sure someone can enlighten us. Biggest one they ever came up with that was night and day was when they adopt grounding and I believe that took 2, I see house built in 60 that only had 3 wire on kitchen and laundry.

That is nothing new, the notes to tables 310-16 through 310-19 has note #3 appearing for the 1st time in 1978 allowing reduced conductor sizes for 3-wire single phase residential services. ***** Remember reduced size.***** 90 amperes on # 2 AL @ 75 degrees C is the correct ampacity.

 

[MrMark]

I would go with the QO series. It is much nicer. No reason to keep it the same IMO, unless you have extra HOM breakers that you can't take back and want to use. The QO breakers are very nice and solid.

 

[srmofo]

Well guys Im heading up there today. I'll let you know what I choose. The reason I said 10/3 instead of 10/2 is because I have a spool I need to use up and I like the thought of having the nuetral in case I decide to add a power light to the circuit like in one of the recent threads.
I also am going to be adding a shutoff to the compressor right next to it. I dont want to have to use the breaker as a switch and it looks like air conditioner flip switch is only about $30 at HD. I think this was the one I was looking at.
http://www.homedepot.com/Electrical...splay?langId=-1&storeId=10051&catalogId=10053