How to Calculate Circuit Breakers for RGB LED Strips with CV + CC Power Supply?

I have -- what seems to me to be an important -- question:

When you ask an AHJ for a ruling like this, and they render one... is this done in writing?

It seems to me you'll have to rely on it later, and it would have to be, but no one's stories about this ever suggest that it is.
 
I have -- what seems to me to be an important -- question:

When you ask an AHJ for a ruling like this, and they render one... is this done in writing?

It seems to me you'll have to rely on it later, and it would have to be, but no one's stories about this ever suggest that it is.
My experience has been "no." Usually it is an oral finding in person or on the phone. This has always been a bit of a concern as when the position changes hands, will the new person have the same opinion? I think if the question involves a lot of money, it would sure be worth asking if they would put it in writing, but make sure you ask nicely.
 
I have -- what seems to me to be an important -- question:

When you ask an AHJ for a ruling like this, and they render one... is this done in writing?

It seems to me you'll have to rely on it later, and it would have to be, but no one's stories about this ever suggest that it is.
@Jay Ashworth I'm certain I've written (bitched) of this on CB before.
Once upon a time I was part of a team who removed a 400 Amp single phase 120 / 240 Volt service and replaced it with an 800 Amp 3 phase 5 wire service feeding an 800 Amp splitter trough supplying two 400 Amp 3 pole fused disconnects via two independent 400 Amp metering cabinets being monitored by one Ontario Hydro modem via two distinct phone numbers. Everything was installed, inspected by a senior AHJ near retirement and multiple copies were signed off by the AHJ including his badge and license number. A couple of weeks later, a comparatively junior inspector at a higher pay level in an office in nearby Toronto overruled and overturned the approval resulting in several of us donating our time to remove and reinstall part of our work to please the off-site AHJ who never personally observed any portion of the install. In my experience, the AHJ always has the final say except when he's overruled after the fact by someone higher up his chain of command. Our local senior AHJ paid us an apologetic courtesy visit, he felt sorry for us and we felt sorry for him.
Excrement, as they say, happens.
To elaborate: The approval and subsequent reversal hinged upon the definition of a conduit nipple. Apparently somewhere in our Canadian code there is a maximum length defining when a nipple becomes a conduit. One of our 400 Amp fused disconnects was feeding a large 120 / 208 panel with 800 Amp main busses. The panel was selected because there was insufficient wall space for two 42 pole panels whereas this single large panel. due to its increased height, would just fit in the available wall space and would accommodate the number and ratings of load breakers required. We had to use an LB and an LL back to back separated by a nipple approximately three and a half feet long to feed this single large panel. Our local AHJ approved our use of measured (matched) lengths of smaller gauge parallel conductors as it was easier on our fingers, and kinder on the copper, to pull 10 conductors through the back to back LB, nipple, and LL rather than to force 5 larger conductors through the contortions required. Apparently, according to the lad further up the pay-scale, the length of our nipple between the back to back LB and LL was too long to meet code. We used a 3 to 2 block, a 1/2" or 5/8" sisal line And pulled the rear bumper off a friend's cargo van to man-handle the 5 larger conductors in via our conduit where the 10 smaller gauge conductors had happily co-habitated for a couple of weeks. Some days I think the plumbers have it better but NEVER make the mistake of referring to a fitter as a plumber. @TimMc @Dionysus Thoughts?
Toodleoo!
Ron Hebbard.
 
@Jay Ashworth I'm certain I've written (bitched) of this on CB before.
Once upon a time I was part of a team who removed a 400 Amp single phase 120 / 240 Volt service and replaced it with an 800 Amp 3 phase 5 wire service feeding an 800 Amp splitter trough supplying two 400 Amp 3 pole fused disconnects via two independent 400 Amp metering cabinets being monitored by one Ontario Hydro modem via two distinct phone numbers. Everything was installed, inspected by a senior AHJ near retirement and multiple copies were signed off by the AHJ including his badge and license number. A couple of weeks later, a comparatively junior inspector at a higher pay level in an office in nearby Toronto overruled and overturned the approval resulting in several of us donating our time to remove and reinstall part of our work to please the off-site AHJ who never personally observed any portion of the install. In my experience, the AHJ always has the final say except when he's overruled after the fact by someone higher up his chain of command. Our local senior AHJ paid us an apologetic courtesy visit, he felt sorry for us and we felt sorry for him.
Excrement, as they say, happens.
To elaborate: The approval and subsequent reversal hinged upon the definition of a conduit nipple. Apparently somewhere in our Canadian code there is a maximum length defining when a nipple becomes a conduit. One of our 400 Amp fused disconnects was feeding a large 120 / 208 panel with 800 Amp main busses. The panel was selected because there was insufficient wall space for two 42 pole panels whereas this single large panel. due to its increased height, would just fit in the available wall space and would accommodate the number and ratings of load breakers required. We had to use an LB and an LL back to back separated by a nipple approximately three and a half feet long to feed this single large panel. Our local AHJ approved our use of measured (matched) lengths of smaller gauge parallel conductors as it was easier on our fingers, and kinder on the copper, to pull 10 conductors through the back to back LB, nipple, and LL rather than to force 5 larger conductors through the contortions required. Apparently, according to the lad further up the pay-scale, the length of our nipple between the back to back LB and LL was too long to meet code. We used a 3 to 2 block, a 1/2" or 5/8" sisal line And pulled the rear bumper off a friend's cargo van to man-handle the 5 larger conductors in via our conduit where the 10 smaller gauge conductors had happily co-habitated for a couple of weeks. Some days I think the plumbers have it better but NEVER make the mistake of referring to a fitter as a plumber. @TimMc @Dionysus Thoughts?
Toodleoo!
Ron Hebbard.

Geez that SUCKS... Honestly I think the local AHJ (ESA) was well justified in letting that pass. Sounds like the guy higher up the food chain was looking to "make his name" and "prove his worth". Seen it a few times. But DAMNIT that's enough of a job to reverse that because of one, sorry to say and to use the language but accuracy matters; TOTAL DICK. ESA out of the mouths of a few retired (okay perhaps a few current ones) inspectors I've talked to is very much "broken" in many ways. Including the way they treat certain customers. For those who do not know the AHJ for electrical in Ontario is ESA "Electrical Safety Authority", and is no longer under the government.

And yes, there is a part in the code that specifies the maximum length of a nipple, though heck if I can remember where not that I have my code book in front of me either.

Really wish for the sake of all involved that noone at the head office had noticed that one. That blows.
 
We had repeated inspections by the NYC FD last year of a renovated and updated alarm system. Every time, same inspector and he would come back to check to see if items had been corrected, then he would add new things to fix. The fire alarm engineer said same guy pulled the same nonsense at Madison Square a few years ago so this guy was well known.

The general contractor finally had their lawyer send a letter detailing all this, the FD sent a different inspector and the system passed, no changes needed.

Some AHJ’s can just be unprofessional dicks is all.
 
We had repeated inspections by the NYC FD last year of a renovated and updated alarm system. Every time, same inspector and he would come back to check to see if items had been corrected, then he would add new things to fix. The fire alarm engineer said same guy pulled the same nonsense at Madison Square a few years ago so this guy was well known.

The general contractor finally had their lawyer send a letter detailing all this, the FD sent a different inspector and the system passed, no changes needed.

Some AHJ’s can just be unprofessional dicks is all.
@SteveB I love your exquisitely precise nomenclature: "unprofessional dicks" as opposed to professional dicks and @Dionysus 's term "TOTAL DICK".
Toodleoo!
Ron Hebbard.
 
If a city signs off on electrical drawings, then something is built, then another AHJ over-rules, requiring a lot of extra expenses...well I'm no lawyer, but it seems like some people would try to make the city reimburse them for those expenses since the higher up AHJ would be implying that the city made a mistake during the approval process, and there would be documentation to prove it.

Is there another power supply manufacturer that puts more detailed info for 120V in their datasheets? I like Meanwell, but extrapolating data meant for 230V unnecessarily increases panel size. In the situation I have to work with, it's probably more difficult to increase panel size than in most situations. Any recommendations for power supplies would be greatly appreciated.
 
If a city signs off on electrical drawings, then something is built, then another AHJ over-rules, requiring a lot of extra expenses...

The plan review for permit - your "sign off" - rarely would include a detailed review of a panel schedule. Plan reviews for permit tend to address big picture items. Have you properly identified the correct occupancy, used a correct construction type, have enough egress, etc. They assume an aisle is drawn wide enough for code, but if the inspector measures it in the field and it's too small, your stuck.
 
A reminder here: "Contemporaneously maintained business records" are generally admissible in court proceedings, as an exception to the hearsay rule.

So, if you're working on a big project like this, *keep a logbook*. In great detail. Yes, it's a a lot of labor. Might save you tens of thousands of dollars in rebuild work.

And the knowledge that you're doing it might rein in a hincky AHJ.
 

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