Josuea1990
Member
- Location
- Florida, USA
- Occupation
- Electrician
Greetings!
Whole house generator with ATS question:
So, it seems to me that in every YouTube video I've watched about standby generator installs with whole house automatic transfer switch on houses that have a 200 A service, and in other, even a farm with A 400 A service with two 200 A panels being fed by a 24 kw generator, they are all just not following 702.4 (b)(2)(a), and they even show that they passed inspection and even had utility come disconnect and all that jazz. I keep scratching my head on ¿how are they passing inspections? Since they all talk very loosely on how to size it. Never mention anything about load calculations in article 220 since the whole house is being automatic transfered, and they just speak about what appliances they would like to run during a power outage as if these appliances were all electric (because if they were not, then why would they be so worry to be able to run them with generator power) things like a/c, cooking, heating and lights and internet they loosely mention for houses that i can clearly see are douple or triple the sq.ft. of my Apt. which i used to compare. They are esentially sizing it based on personal preference.
For example: I live in a 1080 sq.ft. Apt. all electric, and I performed an optional load calc. to see what size Gen. would i be requiered, if I were to install whole house auto. transfer Well, result was 22kw (22kw÷240= 91.66 A) minimum and it makes sense because I have a 100 amp main. At one point somebody applied this same calc. on my dwelling unit in the past and decided to install 100 amp main. And on this videos I've watched they are picking arbitrarily numbers for all electric house (it seems), and clearly double or triple the sq.ft. of my home. For example, on the video with the farm guy he don't have natural gas, so he had propane installed for his 24 kw Gen. feeding two 200 A panels (meaning he never had gas, so he is all electric) and he passed inspection.They all pick 24, 22, 20,18, even 14 kw units.
Just the other day here in florida, even my boss told me on the phone (after I went rushing stretching my 100 ft tape measure around an all electric costumer's house to figure out the total 1968 sq.ft. and took pictures of all nameplates, then sit in the van to make an optional calc. and come up with a 28kw which we don't even carry, since the max we carry is 26kw, to give an estimate (all in 30 min). He says: "well, that 200 A house will do well with a 22 kw. And after the scared reaction for the 22kw price of the costumer who was expecting us to auto transfer the whole house, my boss asked me to say that we can do it cheaper and install an 18kw and they'll be fine (even my boss is picking arbitrarily numbers to make the sale, knowing the costumer wants permit to be pulled, inspection and all that jazz).
How can you explain this videos with inspections passed? Then I tought: "well, maybe they are using 220.87 to come up with a lower number, although they never mention that". But even if they were, how do you explain the Florida videos when even my self went ahead to make sure if we floridians have acces to the maximum demand data history over a one year period from the utility Co. like in some other states. So i called them and asked them for a one year period data on an excell format, so then i could use the max tool on excell to find the highest 15 min or 30 min (however often your utility captures) interval kwh meter registration to then in turn convert that in to kw. Well, at least here in florida that format is not available, all they have is kwh by the hour (hourly insterval registrations) for every day of every month and you have to find it yourself by logging into your account in their website on your energy usage dashboard and by manually looking day by day through the 12 months history for the highest kwh registration wich becomes the same as your highest kw demand per hour, this is insanely time consuming for when you are trying to use this method to calculate for a costumer that's interested on a whole house automatic transfer to come up with the lowest (cheaper) gen. size requiered by code per 702.4 (b)(2)(a) and using 220.87 to comply with the calculation part because the actual historical demand will always give you the lowest number and you could beat the competition and make the sale.
Now between you and me, we know an average 200 A house withouth an EV charger does not see more than 75 amps on a regular basis, and 75x240= 18kw, so in reality, yeah! 18 kw (don't worry about starting currents on A/C generac is rated to withstand them) will do the costumers house based on real history usage peak demand per 220.87, but if i can't get that paperwork from the utility, how can i prove it to the inspector?.
Now, what is going on with me? I'm I the only one worrying to comply with 702.4 (b)(2)(a) ? What if the inspector fail us for not sizing the generator properly, after purchasing materials and generator and start doing the job and all that jazz? Is it that inspectors don't really care because there is no safety hazard involved in it? I mean the worst thing that can happen is that the generator it self won't hold and trip it's own breaker right? or fail due to overloading or simply reduced its lifespan, which ultimately the only affected one will be the costumer, who'll end up with no power and a broken generator. Maybe that is why they are not requiring 702.4 (b)(2)(a) to be followed? What do you think ? I mean, at the end of the day is an "OPTIONAL" standby system.
Whole house generator with ATS question:
So, it seems to me that in every YouTube video I've watched about standby generator installs with whole house automatic transfer switch on houses that have a 200 A service, and in other, even a farm with A 400 A service with two 200 A panels being fed by a 24 kw generator, they are all just not following 702.4 (b)(2)(a), and they even show that they passed inspection and even had utility come disconnect and all that jazz. I keep scratching my head on ¿how are they passing inspections? Since they all talk very loosely on how to size it. Never mention anything about load calculations in article 220 since the whole house is being automatic transfered, and they just speak about what appliances they would like to run during a power outage as if these appliances were all electric (because if they were not, then why would they be so worry to be able to run them with generator power) things like a/c, cooking, heating and lights and internet they loosely mention for houses that i can clearly see are douple or triple the sq.ft. of my Apt. which i used to compare. They are esentially sizing it based on personal preference.
For example: I live in a 1080 sq.ft. Apt. all electric, and I performed an optional load calc. to see what size Gen. would i be requiered, if I were to install whole house auto. transfer Well, result was 22kw (22kw÷240= 91.66 A) minimum and it makes sense because I have a 100 amp main. At one point somebody applied this same calc. on my dwelling unit in the past and decided to install 100 amp main. And on this videos I've watched they are picking arbitrarily numbers for all electric house (it seems), and clearly double or triple the sq.ft. of my home. For example, on the video with the farm guy he don't have natural gas, so he had propane installed for his 24 kw Gen. feeding two 200 A panels (meaning he never had gas, so he is all electric) and he passed inspection.They all pick 24, 22, 20,18, even 14 kw units.
Just the other day here in florida, even my boss told me on the phone (after I went rushing stretching my 100 ft tape measure around an all electric costumer's house to figure out the total 1968 sq.ft. and took pictures of all nameplates, then sit in the van to make an optional calc. and come up with a 28kw which we don't even carry, since the max we carry is 26kw, to give an estimate (all in 30 min). He says: "well, that 200 A house will do well with a 22 kw. And after the scared reaction for the 22kw price of the costumer who was expecting us to auto transfer the whole house, my boss asked me to say that we can do it cheaper and install an 18kw and they'll be fine (even my boss is picking arbitrarily numbers to make the sale, knowing the costumer wants permit to be pulled, inspection and all that jazz).
How can you explain this videos with inspections passed? Then I tought: "well, maybe they are using 220.87 to come up with a lower number, although they never mention that". But even if they were, how do you explain the Florida videos when even my self went ahead to make sure if we floridians have acces to the maximum demand data history over a one year period from the utility Co. like in some other states. So i called them and asked them for a one year period data on an excell format, so then i could use the max tool on excell to find the highest 15 min or 30 min (however often your utility captures) interval kwh meter registration to then in turn convert that in to kw. Well, at least here in florida that format is not available, all they have is kwh by the hour (hourly insterval registrations) for every day of every month and you have to find it yourself by logging into your account in their website on your energy usage dashboard and by manually looking day by day through the 12 months history for the highest kwh registration wich becomes the same as your highest kw demand per hour, this is insanely time consuming for when you are trying to use this method to calculate for a costumer that's interested on a whole house automatic transfer to come up with the lowest (cheaper) gen. size requiered by code per 702.4 (b)(2)(a) and using 220.87 to comply with the calculation part because the actual historical demand will always give you the lowest number and you could beat the competition and make the sale.
Now between you and me, we know an average 200 A house withouth an EV charger does not see more than 75 amps on a regular basis, and 75x240= 18kw, so in reality, yeah! 18 kw (don't worry about starting currents on A/C generac is rated to withstand them) will do the costumers house based on real history usage peak demand per 220.87, but if i can't get that paperwork from the utility, how can i prove it to the inspector?.
Now, what is going on with me? I'm I the only one worrying to comply with 702.4 (b)(2)(a) ? What if the inspector fail us for not sizing the generator properly, after purchasing materials and generator and start doing the job and all that jazz? Is it that inspectors don't really care because there is no safety hazard involved in it? I mean the worst thing that can happen is that the generator it self won't hold and trip it's own breaker right? or fail due to overloading or simply reduced its lifespan, which ultimately the only affected one will be the costumer, who'll end up with no power and a broken generator. Maybe that is why they are not requiring 702.4 (b)(2)(a) to be followed? What do you think ? I mean, at the end of the day is an "OPTIONAL" standby system.
But we lose power all the time, and the MCB on the generator has never tripped.