Tell that to the guy whose oxygen pump fails due to you taking a stab at it and not following the rules for an Automatic Transfer Switch install.
JAP>
Generator feeder questions
- Thread starter LarryFine
- Start date
- Status
Tell that to the guy whose oxygen pump fails due to you taking a stab at it and not following the rules for an Automatic Transfer Switch install.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Your right.
Better to depend on the power company to get the power back on rather than a shoddy generator install.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Shoddy install or not, an optional standby system isn't required to have the kind of reliability as a legally required system.
You can do a pristine electrical installation of said system - if the prime mover has issues, owner didn't pay the gas bill, etc. you still possibly have no power. If it were a hospital, stuff happens and you could in a rare situation still not have power, but at least there you also have trained medical staff supposedly on duty that can intervene and do whatever they believe is necessary.
I'm not arguing that.
And I don't completely agree with the rule.
I'm just saying that the way the code is worded for an Automatic Transfer switch install, (good, bad or indifferent) the backup system is supposed to be sized for the full load.
Not what you think you can get away with, or excuses not to size it for the full capability of the items served without taking into account things automatically started, dumb tenants, or what day of the year it is which is not mentioned in that section.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If you can prove that a 11kva will handle the full load then there's nothing to justify.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
NEC isn't really all that clear on how to determine the load, and as I earlier mentioned I think they crossed the line anyway on this being a design requirement and not a safety requirement. If you overload the generator - that is what overcurrent protection is for. If it is a legally required standby system - IMO overcurrent protection is still all NEC should be concerned with and whatever standard applies that makes it a legally required system is what should apply when it comes to reliability issues.
Nor is it clear on how an inspector is to interpret such an install.
In the absence of a Main Overcurrent Device, He could say (6) 1p 20s equals 120 amps and flag it.
JAP>
JFletcher
Senior Member
- Location
- Williamsburg, VA
Excuse me? As stated numerous times in this thread that we do a load calculation, and also install load shedding modules when required.
Just because I disagree with certain parts of the NEC, or find it lacking in some areas , does not mean I do a shoddy installation.
As for the oxygen machine, now who's cherry-picking examples? My mother was on one for several months before she passed away last year, and power failures were a concern to me. Companies that supply these machines also supply large back up tanks. And as I said before a house generator is not a legally required or emergency backup system, and has no requirement to come on or stay running for any amount of time.
My wife is on insulin, which requires refrigeration. In the event of a power failure, we have coolers and Ice to keep it from going bad. I could install a generator for that, however in the event of something like a hurricane with a sustained power failure, getting fuel to keep it running may be problematic, not to mention that we are prone to flooding here the generator may windup underwater.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Now, now, boys, play nice. :roll:
I finished the install today, but can't test until the LP is done. It took me exactly 50 minutes to reroute the feed through the ATS and connect the new EGC using a split bolt.
The panel only has two 2-pole breakers; a 30a for the clothes dryer, which we agree is not relevant, and a 40a for the range. I don't think there will be a load-shedding issue.
I will post a couple of pics later.
I finished the install today, but can't test until the LP is done. It took me exactly 50 minutes to reroute the feed through the ATS and connect the new EGC using a split bolt.
The panel only has two 2-pole breakers; a 30a for the clothes dryer, which we agree is not relevant, and a 40a for the range. I don't think there will be a load-shedding issue.
I will post a couple of pics later.
We being who? Your not the original poster.
If you do a load calculation and consider that the full load and the generator is capable of carrying that load then good for you.
That's probably what the OP did also, I don't know.
All I asked originally is how a generator with a 70 amp output was backing what seemed to be a 200 amp service with an automatic transfer switch and never got the answer of how that size generator was chosen in the first place.
Many don't realize that when you choose to automatically transfer a load instead of manually transferring it, there are different rules that apply.
I still don't know what the load of this residence is and really don't care.
With the OP indicating no load shed was being used in this particular install made me think he may not have been aware of this rule either and was just pointing out that there is a difference.
If load shed is not in place and there is a large load on an auto x-fr there is a good possibility that the generator could trip out and your concern about a power outage for someone who was on an oxygen machine would be increased two fold because the backup system that was installed to prevent such a tragedy didn't.
JAP>
- Occupation
- Licensed Electrician
JFletcher
Senior Member
- Location
- Williamsburg, VA
If someone with a home oxygen machine ask me to install a generator for that reason alone, I would decline, for the reason that I cannot guarantee, Fail-Safe, 100% insure that generator would start under a power failure. Even if I could include such suicidal language with the installation, if they are not maintained properly, such a warranty would be good until the first maintenance interval at best.
Home oxygen generators come with rather large backup oxygen tanks good for a day or more. Anyone that cannot transfer a hose from the portable generator to the oxygen tank is in too bad of shape to be living in a house anyway. Believe me, I know. I wish I didn't know, but I know. RJ, I share your concern about such a thing happening, I just do not believe a generator is the proper answer to that particular problem
Home oxygen generators come with rather large backup oxygen tanks good for a day or more. Anyone that cannot transfer a hose from the portable generator to the oxygen tank is in too bad of shape to be living in a house anyway. Believe me, I know. I wish I didn't know, but I know. RJ, I share your concern about such a thing happening, I just do not believe a generator is the proper answer to that particular problem
JFletcher
Senior Member
- Location
- Williamsburg, VA
To answer your question, we being me and the company I work for.
And Larry, I look forward to your pictures.
And Larry, I look forward to your pictures.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
I am the O.P., and it seems my last post was overlooked:
Plus, there are only twelve 1-pole breakers, so, as I said earlier on, a 100a service would have sufficed. This 200a service was apparently an upgrade, probably from fuses, which is also why the external main disco, as the panel is only about three feet from the outside wall penetration.
Plus, the inside panel, a SqD HomeLine 20-space, contains a redundant main breaker, probably chosen being cheaper than an equivalent M/L panel. As for the choice of the 16Kw, the customer originally asked for 11 Kw, but liked the larger unit for $1K more, and more profit for me.
As for power consumption, this guy is older, single, disabled, sits in front of his computer (running Windows 95!) most of the time, and keeps the house dark. The water heater and furnace are oil-fired, and again, there is no air conditioning, so the range is the only real loading concern.
Plus, there are only twelve 1-pole breakers, so, as I said earlier on, a 100a service would have sufficed. This 200a service was apparently an upgrade, probably from fuses, which is also why the external main disco, as the panel is only about three feet from the outside wall penetration.
Plus, the inside panel, a SqD HomeLine 20-space, contains a redundant main breaker, probably chosen being cheaper than an equivalent M/L panel. As for the choice of the 16Kw, the customer originally asked for 11 Kw, but liked the larger unit for $1K more, and more profit for me.
As for power consumption, this guy is older, single, disabled, sits in front of his computer (running Windows 95!) most of the time, and keeps the house dark. The water heater and furnace are oil-fired, and again, there is no air conditioning, so the range is the only real loading concern.
Plus the fact that if you don't size the generator for the full load the garage door wont open so the car is left parked on the street and will pop out of gear and roll down the hill and ram into a bus full of nuns.
JAP>
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Okay, a couple of pics; nothing special.
![1522722435134[1].jpg](https://forums.mikeholt.com/data/attachments/11/11115-cc529f51ff25aa6a806783c2d989c422.jpg "1522722435134[1].jpg")
![1522722435483[1].jpg](https://forums.mikeholt.com/data/attachments/11/11116-eb5c4a032a54b2ec67ab481bccad1428.jpg "1522722435483[1].jpg")
- Status