Originally Posted By: rskinner
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http://www.nachi.org/bbsystem/usrimages/P/PA010014.JPG ]
http://www.nachi.org/bbsystem/usrimages/P/PA010014.JPG ]
Originally Posted By: Greg Fretwell
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If the breaker is not tripping it is not a problem. I imagine the guy put a breaker in based on wire size because he didn’t understand NEC 430 and 440.
The min and max breaker are exactly what they say. The min is based on nuisance tripping and the max based on protecting the wire against a short.
Minimum circuit ampacity is the wire size, based on 310.16, the 125% deal is altready in that number. On smaller wire sizes the terminal temperature rating will determine what column you use. Larger sizes are usually 75c.
In motor circuits the wire size will not usually correspond to what you usually see with breaker sizes. The overLOAD protection is in the motor or starter so you are just protecting the wire with overCURRENT protection (shorts).
You can see something like a 14 ga copper wire on a 40a breaker (a 1HP motor on 120v). There are even more complex computations going on in a HVAC, like multiple motors and non-motor loads so they give the engineering to the installer on the sticker.
Originally Posted By: bbadger
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This is a great label it is as straight forward as it looks.
It has to have at least a 50 and no more than a 60 amps fuse or breaker.
The wire size will have to be 8 AWG copper minimum.
--
Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: bbadger
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| Greg Fretwell wrote: |
| If the breaker is not tripping it is not a problem. |
Greg this label lists a 50 as the minimum breaker or fuse, IMO that amounts to a 110.3(B) violation tripping or not.
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Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: pabernathy
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yep…ratings on the nameplate are king here. As greg stated the Min is usually what the OCPD is installed at but it could very easily be the max as well…but the Min Supply Ckt. is set in stone in that you have to use the correct conductor for this part of the application.
I think greg is right here......the guys just place in a breaker because he wanted to protect the conductor....not knowing the motor and compressor factors greg posted are built in.
Man.....when all else fails break down the plate as listed and be glad it did not have a circuit breaker protecting it while the plate said FUSE only......lol
Bob...you are too fast or I type too long....probably the second one..lol.....man at the cost of AL....make sure the terminals can accept AL and run # 6 AL cheaper than CU....have you seen the price of copper...lol
--
Paul W. Abernathy- NACHI Certified
Electrical Service Specialists
Licensed Master Electrician
Electrical Contractor
President of NACHI Central Virginia Chapter
NEC Instructor
Moderator @ Doityourself.com
Visit our website- www.electrical-ess.com
Originally Posted By: bbadger
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| pabernathy wrote: |
| man at the cost of AL....make sure the terminals can accept AL and run # 6 AL cheaper than CU....have you seen the price of copper...lol |
Your right. 
They (the company) don't let me run AL except for temp feeders so I forget about it.
--
Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: Monte Lunde
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Robert,
You got the correct answer from Greg, Bob and Paul and the best thing there was not any confusion in those answers like some of the past posts on Electrical, also I think your question was the FIRST that all three have responded too.
This Electrical Forum will become more popular now, with you three answering a question.
I again thank you Greg, Bob & Paul.
--
Monte Lunde CCI, CCPM, CRI
Viking Construction Services Inc.
Originally Posted By: pabernathy
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Dang…thanks Monte
Can you guys FEEL the love in the room...
But truthfully....... we should be posting the NEC or Code in a way that is not too complicated and a way HI's can use it. I will NOT try to go into a answer from someone who is not an HI that wants to know about Triple Harmonics or Inductive Reactance......thats another forum....lol
In fact BOB mdoerates over at one of those other forums...lol...You go BOB ! ( look for him...iwire )
As the unofficial spokesman for Bob and Greg ( which I have not had the true pleasure of really meeting yet formally ) any myself we are glad to be here and look forward to helping out.
Now you like me know...remember that on my late night posts...lol....but trust me I wont ever belittle you about electricity as I learn new stuff every day. we will just keep it what i call CODE.
Yet another reason to join the NACHI?
Now.....does NAHI or ASHI got THAT........no way bubba....
Note: I like ASHI so no one start bashing...lol......just talking about features for members...lol
--
Paul W. Abernathy- NACHI Certified
Electrical Service Specialists
Licensed Master Electrician
Electrical Contractor
President of NACHI Central Virginia Chapter
NEC Instructor
Moderator @ Doityourself.com
Visit our website- www.electrical-ess.com
Originally Posted By: Greg Fretwell
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Bob is absolutely right that this is a 110.3 violation (not following the MFG instructions) but nobody burned their house down by putting in too small a breaker. If it trips it should get replaced with a conforming size. The reality is these new high efficiency refrigeration compressors simply are not the power hogs they used to be.
When that puppy starts getting old and they have to put a hard start kit on it you might find out you need the "max" breaker. 
Originally Posted By: rskinner
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Thanks to all you guy’s who replied. I always try and cover my butt and report what I see and not what I may or may not know to be true.
Originally Posted By: pdacey
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Robert,
I noticed the manufacture year as '01. Was this a 4 year old house or an older house where the AC was replaced? It is very common to find an incorrectly sized breaker on an AC if it is a replacement unit. A lot of contractors will replace the condenser and not check the breaker in the panel. I questioned a tech. once on this and he said "that's an electrician's job, I'm not an electrician". But he never informed the client that the breaker should be down sized either. 
--
Slainte!
Patrick Dacey
swi@satx.rr.com
TREC # 6636
www.southwestinspections.com
Originally Posted By: rskinner
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Hi neighbor. The house is only 4 years old. I think the sparky was just lazy or the A/C installer didn’t care because the unit is only 2 feet away. The conductors could of been replaced PDQ.
Originally Posted By: dandersen
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| pdacey wrote: |
| Robert,
I noticed the manufacture year as '01. Was this a 4 year old house or an older house where the AC was replaced? It is very common to find an incorrectly sized breaker on an AC if it is a replacement unit. A lot of contractors will replace the condenser and not check the breaker in the panel. I questioned a tech. once on this and he said "that's an electrician's job, I'm not an electrician". But he never informed the client that the breaker should be down sized either.  |
That's BS!
Mechanical contractor's license covers electrical service connections to the equipment. If the service panel is inadequate, the mechanical contractor is liable for hooking the equipment to an improper power source.
Originally Posted By: lkage
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| pdacey wrote: |
|
It is very common to find an incorrectly sized breaker on an AC if it is a replacement unit. |
Probably 40% of 'em around here.
--
"I have never met a man so ignorant that I couldn't learn something from him."
Galileo Galilei
Originally Posted By: dandersen
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Disconnect panels at the HVAC unit should be replaced whenever a unit is changed. The service panel does not cost very much when you consider you may void the warranty of the new equipment for having improper power supply.
Disconnect replacement is the job of the mechanical contractor not an electrician. A disconnect and proper size wiring and breaker should accompany the unit to the job site during installation. If this is not done, the competency of the mechanical contractor should be questioned.
I find scores of overheated, outdated, insufficient circuit breakers and fuse blocks on brand-new equipment. Deteriorated or loose connections in the service panel may cause an imbalance of electrical power which could destroy the compressor. If this gets caught, it will void the warranty.
Originally Posted By: bbadger
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| dandersen wrote: |
| Disconnect replacement is the job of the mechanical contractor not an electrician. |
David you are assuming that the licensing rules are the same everywhere, they are not. 
Here in MA electricians would handle the disconnect.
It would require a electrical permit and inspection, you must have an electrical license to obtain a permit.
--
Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: pabernathy
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Yes, in VA it is the same that the HVAC guys are not allowed to connect to OUR disconnect which we have to provide for them. The bad part is we place the disconnect many times and it is just the DISC because the unit has not been set yet…they come and set the unit and WHAMO…set it right in front of our DISC…this is not allowed…so GUESS who ends up moving…The HVAC man’s unit…ours was their first…lol
–
Paul W. Abernathy- NACHI Certified
Electrical Service Specialists
Licensed Master Electrician
Electrical Contractor
President of NACHI Central Virginia Chapter
NEC Instructor
Moderator @ Doityourself.com
Visit our website- www.electrical-ess.com
Originally Posted By: Greg Fretwell
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Around here it really depends on whether they pull a permit. A lot of condenser swaps happen as a “repair” and theoretically it is a “like kind” swap that would use the same disconnect. If this gets treated as a system install they should be getting an electrical and mechanical permit. That doesn’t always happen and the HVAC guy will do all the electric.
It is fairly muddy where a “Repair” stops and an “installation” begins.
There is a lot of “George Washington’s Hatchet” going on.