Still not working and I’m befuttled.
Original install (now that I have been up to the roof) had a Home
Line exterior two space
breaker panel
fed by #8
wire and two phases measuring 123v and 213v between them. There was two dual 20A breakers in the two slots making four circuits in the panel. All is fine so far. Below the panel is two outdoor
outlet (bell boxes) that have two each un-GFCI mounted duplex receptacles. The
Edison receptacles are split wired for individual 20A circuits. All seems fine with the wiring so far.
Our original installer a few days before
hand ran a 250'
Edison cable of 12/3 from one of the roof top outlets above (none of the other outlets are in use) down from the roof and the side of the building to the
cove I’m lighting. From there, I hooked the 12/3 directly hot directly into the
line side of a 20A compact magnetic
circuit breaker. Load side of the
breaker along with
neutral went into their terminals on a 500
KVA 120v to 24v
transformer. This
transformer was metered out in the shop and tested out in outputting 24v. Even had the other ME where I work verify that what I was thinking with the inadequate instructions for what to tap on the
transformer and which was the hot/
neutral was which, much less in general how I was doing it and got the thumbs up from him. My
transformer was good and should work. Tested good all was good. From the output side of the
transformer another 20A
circuit breaker was installed as per the
transformer’s instructions in me replacing a
fuse with
circuit breaker but otherwise following the plan for what to tap, which than went to a Marithon
block and barrier strips for the 24v
power.
Box was grounded and installed about 34 high in the peak of the
concave arch. This as opposed to on the roof a few stories above where we will have had to run #1
wire size to do 20A at 24v given a 250' run - once we started to do the math. Urr, I started to do the math given it was someone else’s project I was only providing the boxes for and I was now stuck with it. Sure, it will have been nice to
park the
transformer on the roof - easy access to it’s
circuit breakers... than the
voltage drop comes in.
About 320 5w/24v lamps were divided fairly evenly into five circuits which ran all over the 30' archway in chains of belt lights that had various taps all over the place for branches of each
circuit. Sunburst
effect for the most part in following the windows. All taps were weather resistant and it has not rained in the past couple of days. Various taps and all belt light circuits were of 16/2 SPT-2
wire (though marked that way, in stripping it, it more seemed like #12
wire than #16
wire in use for the belt lights), of the taps some needed short extension cables added on to make the tap longer. 16/2 outdoor cable (similar to the
SPT zip cord but made for outdoors) was used for the short no longer than 5' and normally 6" extensions where needed between say branches or from the end of a string to the
transformer.
First attempt to
power the thing up on Wednesday Morning was disastrous.
Line side of the
transformer breaker tripped. Ok fine, it’s and inductive load going
thru a
transformer, I try it again and the load side
circuit breaker trips.
Line side stays on - great... Re-set the load side of the
transformer breaker and it trips again and again instantly. That’s bad. (By the way as I write this, I’m adding to my 4AM at the shop pull list for what to bring so it’s good in a way at least in thinking out the problem to describe so far what I have observed.)
So, we have the load side of the
transformer compact
breaker now
tripping and unlike the
line breaker, it won’t stay on after being re-set un-like the
line side
breaker. Believe that initially, when I powered up the
transformer as per the instructions on some past transformers I wired, I had the load side
breaker already on, but I could be mistaken on the order of which was already on first and or what some past instructions said to do in powering it up. Anyway, it seems to me that each time I was leaving the load side
breaker on in re-setting and powering up the
line side only for after the initial
line breaker again
tripping each time. After the innitial
tripping of the
line breaker, it stayed on and has always worked. At some
point no doubt I will have had the
line side on and re-set the load side also only for it to instantly trip.
By this time, it was fairly well understood that it was either something in the belt lights causing the load side
breaker to trip, or a bad
circuit breaker. Both breakers I am fairly well certain were both 20A, and connected in the proper
line/load wiring but I saw some rubbed away red paint on the lever of the load side
breaker meaning it was not a new one - it was a used
circuit breaker. This
circuit breaker had a some time in the past life as a
phase Y to something so potentially in not being new, perhaps it was a bad
circuit breaker.
I confirmed at least at the time this assumption that I had a bad
circuit breaker on the load side by way of one by one of the five circuits - while 30+ feet in the air and kind of leaning back at a bad angle to get into the box, that it was the
breaker that was at fault - I thought. Out of five circuits, I removed one by one from the
barrier strip they were plugged into and each time under
power from now four circuits, the load side
breaker was still instantly
tripping. So, given by process of elimination in out of five circuits, removing any one of them did not stop the
tripping of the
breaker, it had to be the
circuit breaker. I bypassed the wiring to and from the used and potentially bad
circuit breaker and powered up the lights now by way of only the
line side
circuit breaker.
All circuits worked now. Lots of not screwed in all the way lamps or lamp
base taps that didn’t pierce a
conductor to troubleshoot, but an hour later afterwards everything worked and all circuits were up and running with all lamps working now. Problem solved in near miss, bad
circuit breaker on the load side. This I thought - project done time for my 10 day vacation.
About four hours later I got the
call that the belt lights went out and in attempting to re-set the
circuit breaker from the roof, it just kept re-tripping. Up to now, the
circuit breaker sub-panel on the roof has not been a problem. That was the original post on this subject about
voltage drop as the assumption of what now was going wrong. Since the still connected
line side
breaker was not
tripping, and it was nearest to any potential fault, and it might take a while for a
circuit breaker powering up a
voltage drop problem to heat up enough to trip, this was very much assumed to be the problem. Simple answer or if in the roof they were using a
GFCI and who ever kept trying to re-set the thing was calling it a
breaker, that was also simple enough still under this explination of the problem or perhaps a
lag time on a bad
GFCI that took a while to trip. Certainly if the
breaker nearest the
transformer on it’s
line side was not
tripping, one of the two possibilities with the
house power or the cable
drop was the answer and easy to solve so I thought at 10:30 PM at night as I was leaving the shop after two and a half hours there spent packing my tool kit for the day and finding what outlets to use. Lucked out on the outdoor
twistlock outdoor
cover, it went right into the already installed Bell box - simple as anything to install a single
phase three
phase thirty amp
plug into the already installed box. Pull their wiring and
outlet, install mine.
Given this assumption of it being the wiring and not the
transformer or the belt lights the solution was easy. Could have been out of there in two hours given my assistant for the day or someone after him didn’t grab one of our 100' pieces of 8/5 cable. This much less for the 100' run he did get on the truck, it was not one of ours - didn’t have any of our markings on it and seemed to be 10AWG instead of 8AWG. By chance he managed to find a cable that never should have been put into
stock and was not the right
wire gauge, than somehow between him being sure he pulled two 100' cables and a 50' one, lost the other 100' cable. No problem, it’s 6AM on a
holiday from work morning - who can I
call to Un-lock the shop, grab a cable and drive 60 miles in running out another cable for us... Ah’ a salary staff sucker with keys to the shop person like me born every minute, or at least one that woke up to my ringing their phone finally. Of like six or seven people with keys, I got lucky.
So under today’s assumption, doing 12ga
wire for 250' even if at only 16.66 amps roughly, once you added in
voltage drop or extra loading due to inefficiencies of the
transformer, you now were over 20Amps assuming a 120v
power supply that in theory could be less in making the amperage at the
house breaker end go up some. Since it was the
house breaker or
GFCI receptacle at that
point still unknown, and the remaining
line side of the
transformer circuit breaker, other than in initial
power up was not blowing first as it should, it was assumed that this was a
voltage drop issue. Such a
breaker in having a few amps more than it was rated for would take a
bit of time to trip given it won’t trip under a other than abnormal load before it reaches the 127% ratio for the
circuit breaker. In other words, it sounded perfectly reasonable that in an inductive incandescant loading, that it potentially in out door freezing conditions could take like four hours for a
circuit breaker to trip and once heated, no longer re-set once warm given say a 22 Amp loading on the
circuit. There was no
GFCI in use so once I got up to the roof
power supply it was definitely not some bad
GFCI having problems with the
lag time generated between hot and
neutral due to the
transformer that powers up from both the hot and
neutral. Simple and should have done the trip. #8
wire feeding a 16.66 amp load should have been more than sufficient.
Going back to what I crossed out in the
voltage drop assumption, given it was a bad
circuit breaker on the load side and bypassing it solved the problem in that the
line side
breaker was not
tripping, I just wrote this off as a fluke occurrence and it still might be where you might have a bad
circuit breaker initially and the
voltage drop was a secondary problem. I at least A.S.S.U.M.E.D this. Little did I know that perhaps that load side
breaker in
tripping than being bypassed was working properly and the
line side
circuit breaker perhaps is the bad one now in having tripped I believe once initially and now becoming just a
switch. These are expensive magnetic mini-breakers, one would assume that if they go bad, they do so in the tripped position and stay off but who knows. This morning’s disappointment of it still
tripping the
house power circuit breaker after I switched to a now combination of (by accident 100' or 75' unknown of) 10/5 and 8/5 cable unsettles me in that above problem of
voltage drop having been solved as theory I was satisfied with and not related to why it’s still
tripping now.
Seemingly it was nothing about
voltage drop. To test this and given it was #8
wire feeding the dual
circuit breaker, I woke the project manager for this install up again at 7AM. He needed to get his rear over to the job site and bring with him a 30A home
line single pole
breaker. Dutifully, he got there by 9:30 with the store opening at 10AM and no longer a possibility of setting up a large Geni lift in front of the main doors.
I installed the 30 Amp
circuit breaker to test a theory anyway from the roof. Either we will be golden in my
voltage drop calculations having been still off - even if way outside of theory, or at least it would
power up the
transformer and work or trip the
transformer’s remaining
line side 20A
breaker. This or at least pop the prospectively 20A or unknown main service panel’s
breaker. The
wire feeding this sub-panel should be safe for 30A as with all the cable now feeding the
transformer.
Popped the brand new 30A
circuit breaker in that sub panel on a constant attempt basis. My world just sank. We have 123v, a good
neutral, I detect no short between hot and
ground and no short between
neutral and
ground between here and the lights. I do detect a
continuity between hot and
neutral between the sub-panel and the lights, but given it was still hooked up to the
transformer and it’s load, I should. Once un-plugged, all jumpers on the roof - like 200' of them showed good lack of
continuity between conductors. It of course was too late to set up the lift and un-plug the
transformer and test the dropping down the side of the wall cable. Could be that given this in theory at least 100' cable that didn’t belong to us yet was pulled for the show, and is 10/5 and not 8/5 but the longest length I had to work with had a short on it’s female end. The male end once opened looked fine but the female end I did not inspect. One would also assume that should there be a short between hot and
neutral on it, such conductors will have burned up given the 30A
circuit breaker took a few moments to trip in giving me enough time by way of hearing the
breaker thinking about it, say some stuff not public to repeat.
Snap crackle and pop was not in my lingo at the moment. That brand new 30A
breaker tripped, than upon re-setting instantly started
tripping.
So, it was 9:45 AM of the biggest shopping day of the year and we in theory could set up a 40' Geni Personal Man
Hoist on center in front of the main doors, which would tend to make them not work, to the very high
profile store, or we could put our
tails between our legs - project manager, truck
driver/assistant who was no slouch by way of help (and at double overtime in pay) and I the guy (on vacation now) that had it all figured out and apologize that the store would now three days late not get their Christmas lighting
effect again today. Possibly in the morning or by Tuesday six days late if I have to order a new
transformer and mount it into a new box. Four window every morning between 6AM when security gets there and 10AM in the store opening, should have been long done by now - but these are new lights and there is some wee... trouble shooting to do in the
system - like it’s blowing the main
breaker.
I’m about ready to rip this whole thing down and
lay it down on the shop floor so as to re-do it all and re-wire it under factory/shop conditions. Already an assistant at double time pay scale (me being salary and on vacation in losing money), a two day rental of a lift at $200.00 a day now being rented for a week given a two day expected install, gas, $30.00 per car parking fees per day
etc. this project just lost money and is still not working. Luckily as long as he doesn’t have to do his re-assigned new show the original ME for this project in the morning again, he might be on-site to help me troubleshoot. Guy is salary also but I don’t feel bad for him in comparison.
We will at 6AM after I’m at the shop at 4AM, the project manager up on the roof in reading a
book and waiting to flip on and off the
circuit breaker, the #4 electrician at our shop and I troubleshooting the problems 30' up in the or around the 30' dia. arch. #3 has also been consulted and doesn’t know. We don’t want to bother #1 electrician as it would take hours and get nowhere, much less he would necessitate being on the time clock to offer advice for as long as we could bear a non-decision.
Chatted over the phone with the other electrician, we have our theories. His first question was did I follow his
layout of the lighting plan to the letter? Yep, unfortnately the project manager left that plan locked up inside an electrical closet while the store was closed, but to the best of my knowledge, I did follow the plan in circuiting it. Still, it’s not very likely that one
circuit has too much amperage, first these are 5w lamps in say 20 to 50' sections at 24v. Should be sufficient not to blow a 30 amp
circuit breaker even given 16ga short jumpers at times used.
Almost cross out wrong circuiting amongst the five circuits of 320 lamps. Could be however in that like #34 electrician at the shop was wiring part of it, and I did the later splices, perhaps and very possible, that we have two separate circuits linked into a parallel situation by way of splicing. Would not be bad unless we now had a hot/
neutral or as other ME at the shop corrected me on, Hot/
return given it’s following the
transformer, shorting situation. Don’t believe it’s this but such is possible and would trip a
breaker.
One would think it would both trip the
line side of the
transformer breaker and do so of either it or the sub-panel
breaker immediately, but given the size of the
transformer, perhaps it did take a while to get overt enough to hours after it all worked, cause real problems.
Could be that some lamp
base is shorting between conductors, could be that more than one lamp
base on a number of circuits is doing so. This would as with the above if in combination with and or the cause explain why by way of individually testing each
circuit, why the load side
breaker kept
tripping. By way of last minute fixes to individual lamps not working, I certainly saw enough lamp sockets that had their cable piercing sockets that were bent thus not conducting. One would think that such sockets that pierced but shorted might be dim at least or not work due to the short by way of lamp, but who knows. No lamps seemed dim overall but it was
daylight and who knows what equates to a 30a but high resistance short.
Gonna be more than one problem if that’s the case - I hate it when there is more than one problem to troubleshoot at a time. One thing I did not do in troubleshooting that bad
circuit breaker was to troubleshoot one
circuit powered up at a time. I was powering up four out of five in
tripping the
breaker but did not attempt one at a time. This will have shown much thus keeps alive the above as theory and real pain in the rear to troubleshoot.
I was amazed enough that the splices all worked, now I get to look at 320 lamp bases for what is the short?
Another possibility is that the
transformer while outputting 24v and not
tripping my bench test
circuit was bad. It otherwise went bad by way of the above short in circuits which could take four hours to go bad, or that the 320 5w/24v lamps loading on it were more than 500KVA of the
transformer rating - my mistake, or that it’s really a lot more than 320 lamps and the
transformer was overloaded than melted down internally. This
transformer if melted down and shorting, while confusing that the
line side
breaker is still yet to trip under a 30A load, would also easily explain the 4 hours of it working and now
tripping.
Bad
transformer by way of some short still in the
system we would also have to find - could be metal to cable or lamp
base or bad circuiting, but this would be hard to figure out, much less still require fixing now both
transformer - now shorted at the
line end and at the load end trouble shooting.
Thanks again McMaster Carr. Just put on Will
Call pickup for the morning after I if necessary leave the store again with tail between my legs a 30A
transformer 750KVA *given I understand my math, and all parts required for a Sunday- going
Sunday trouble shooting four hour period of troubleshooting. Once I again
wire the thing, it should in replacement solve the problem of either over wattaging of the lamps or should we have shorted the
transformer, it’s direct replacement once we figure out what shorted it.
Perhaps I’ll
park the project manager outside the store initially first to count lamps so as to figure that out or cross out that first. Project manager is slave labor on this project at this
point - you chose this
system of low
voltage lights, you are my ***** until they work and remain working.
That’s where I am at now. Still don’t work and I’m seriously fustrated by way of I know my connections are good in theory at least. If they are not, it’s going to be a huge problem to troubleshoot this 1' on center 320 5w/24v lamps, circuited into five circuits over a 30+' dia. One cannot even imagine the amount of things to check here.