40 amp breaker poping with only 25/30 amps of current??
- Thread starter DIGITALHIPPY
- Start date
knna
Member
Maybe explaining it from other point of view will help. Think you have 2 generators wich give 120V each and 20A. If you need to get 40A and 120V, you put them in series, but if you need 240V, then you put them in paralell to get a 240V and 20A line.
You cant double both, or you double amperage or you double voltage, not both at a time. When converting two 120V lines to one 240V line, it works the same way: you double voltage, but current rating keep the same.
In order to have 40A in that 240V line, you would need to upgrade both 120V lines to support 40A each, if possible, by upgrading wire section to one supporting 40A and changing the magnetotermic (wich is what set a current limit according to wire section, in order to prevent a fire due to too much current for a given wire section).
On the other hand, you were using 5 1000K ballast. 1000W/240V= 4.16A each plus about 4-7% losses on the ballast, it means about 4.4A each. 5 ballast at 4.4A each are a total of 22A. Magnetotermics size are determined with a safety margin well below the actual dangerous amperage of the section wire, but they may have wide tolerances (up to 15%). So its probable it worked for 2 days because the amperage was just in the magnetothermic limit. But it was just a matter of time it popped.
And i think your ballast are very good (little losses) and probably underpower slighty. And aditionally, with an excelent power factor, close to 1: you may think that the ballast may require more current than what it consumes (those ~4.4A), more as lower the power factor. Often it isnt a problem, because that excess current called "reactive" isnt billed by the electric company, but it need to flow across the wire anyway. A bad ballast, not compensated may require up to 30% more current flowing (although not burned). Im surprised it worked for 2 days with a such reduced margin, it should mean your ballast are very good (power factor very close to 1 and little losses) or the line had popped on the first igniting.
I think you should load that line with just 4 ballast, its the easier solution. And think you are lucky due your ballasts, other people with 4 1000K may not be able to run them on a 20A line (with low quality ballasts).
Peace
knna
You cant double both, or you double amperage or you double voltage, not both at a time. When converting two 120V lines to one 240V line, it works the same way: you double voltage, but current rating keep the same.
In order to have 40A in that 240V line, you would need to upgrade both 120V lines to support 40A each, if possible, by upgrading wire section to one supporting 40A and changing the magnetotermic (wich is what set a current limit according to wire section, in order to prevent a fire due to too much current for a given wire section).
On the other hand, you were using 5 1000K ballast. 1000W/240V= 4.16A each plus about 4-7% losses on the ballast, it means about 4.4A each. 5 ballast at 4.4A each are a total of 22A. Magnetotermics size are determined with a safety margin well below the actual dangerous amperage of the section wire, but they may have wide tolerances (up to 15%). So its probable it worked for 2 days because the amperage was just in the magnetothermic limit. But it was just a matter of time it popped.
And i think your ballast are very good (little losses) and probably underpower slighty. And aditionally, with an excelent power factor, close to 1: you may think that the ballast may require more current than what it consumes (those ~4.4A), more as lower the power factor. Often it isnt a problem, because that excess current called "reactive" isnt billed by the electric company, but it need to flow across the wire anyway. A bad ballast, not compensated may require up to 30% more current flowing (although not burned). Im surprised it worked for 2 days with a such reduced margin, it should mean your ballast are very good (power factor very close to 1 and little losses) or the line had popped on the first igniting.
I think you should load that line with just 4 ballast, its the easier solution. And think you are lucky due your ballasts, other people with 4 1000K may not be able to run them on a 20A line (with low quality ballasts).
Peace
knna
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J
JamesChong
Sorry, hate to butt in. Since we are on the subject.
00420, you think it would be safe for me to run one of these units on a 30 amp dryer outlet? Planning on running 4 x 600HPS during the day and the same at night. So, I would be running 4800 watts, but half at a time. Don't want to burn my place to the ground.
Killer thread with lots of info. Thanks for sharing everyone. Have a nice weekend all.
Later,
BG
00420, you think it would be safe for me to run one of these units on a 30 amp dryer outlet? Planning on running 4 x 600HPS during the day and the same at night. So, I would be running 4800 watts, but half at a time. Don't want to burn my place to the ground.
Killer thread with lots of info. Thanks for sharing everyone. Have a nice weekend all.
Later,
BG
JamesChong said:Sorry, hate to butt in. Since we are on the subject.
00420, you think it would be safe for me to run one of these units on a 30 amp dryer outlet? Planning on running 4 x 600HPS during the day and the same at night. So, I would be running 4800 watts, but half at a time. Don't want to burn my place to the ground.
Killer thread with lots of info. Thanks for sharing everyone. Have a nice weekend all.
Later,
BG
sry homie but i dont even know wtf that is.... hahaha
i do know 4 x 600 = 2400/240v=10amp's and if you put that on a 30amp line it should run 24/7 like you are asking.... but then again you could have crusted dryr wire from the 50's
edit: more then likely you will be running at 220v + line voltage drop so more like 12-13 amp's
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You need 8 gauge wire for a 40A breaker, a 20A double pole does not equal 40Amps
Table 310-16 1999 NEC code book, ignore the scribbles on the side and the highlighter, its from years ago when I was in school still.
That table is probably the most important page of the whole book.
Table 310-16 1999 NEC code book, ignore the scribbles on the side and the highlighter, its from years ago when I was in school still.
That table is probably the most important page of the whole book.
J
JamesChong
00420 said:sry homie but i dont even know wtf that is.... hahaha
i do know 4 x 600 = 2400/240v=10amp's and if you put that on a 30amp line it should run 24/7 like you are asking.... but then again you could have crusted dryr wire from the 50's
edit: more then likely you will be running at 220v + line voltage drop so more like 12-13 amp's
It's a 8 light unit that has two triggers. You have a timer for one side and another timer for the other side. Kind of like a flip flop but with all 8 ballast and not 4. I can split up the 8 lights. To run half the light during the day and the other half at night. Less amp draw and less of a high wattage pattern if the light company is watching with software.
What's this wire from the 50's? If I got to, I'll just run a new wire. Since the wire is close to the box.
Thanks,
BG
yes it is..... that slipped my mind and was thinking 2 #10's would work but not be to code....luciano28 said:
DH get a 2nd double 20amp for that light..... and run it as 3 on each....
once you do your going to have to change that main to a 60 what size wire do you have running that sub? i hope #6
JamesChong said:
if its a 8 light unit then its probly going to be wired for 50 or 2 x 30 i have seen them both ways.... i would run new wire to a sub like DH is then go off it.. it's the best way IMO and you know it's right for the cost of that unit you can build a sub with all that shit built in
W
Whatever
LOL...I'm in over my head here but do understand the 10/2 and 10/3 thing. To be safe ran 2000 watts on a 240 dryer circuit like 8PM to 8AM my first indoor...and clothes were done only during the reverse. I was fortunate in that the house had 50's 2 conductor to the sockets but the dryer and hot tub circuits had 'fresh' lines coming from the main panel at the meter. I actually tapped off that dryer circuit and also ran the vent fans during lights on.00420 said:
W
Whatever
Thanx OO420 as I've learned a bit more here...definitely a wiring dweeb.
00420 do you think the correction factors for temperature should be used when wiring a grow room? I mean I hope everyone keeps their temps under 30C(86F), that is what the table is based on, up to 30F, but we all know things can happen and people should be prepared for it when wiring. What do you think the max temp a grow room could get to? Without it being on fire, lol. I know in our furnace room at the mill we have wire 2 sizes too big for the overcurrent device(fuses and breakers are OCD's) because of the ambient heat. There are correction factors for the amperage rating of each gauge wire according to the ambient temperature.
Im not sure why its all in Celsius but here is the table typed out(all Celsius)
21-25 1.08
26-30 1.00(the table is based on this temp)
31-35 0.91
36-40 0.82
41-45 0.71
46-50 0.58
51-55 0.41
56-60 ------
61-70 ------
So say it could get up to 34 Celsius, then 40 amps X .91 =36.4 meaning 8 gauge wire would be rated at 36.4 amps at those temperatures
Fwiw guys Im a currently laid off for the summer industrial electrician but I havent wired anything residential in 5+ years and my job doesnt require much wiring, more troubleshooting motor controls and working on PLC's so I been reading this thread interested but not really wanting to get involved, for one Im rusty with this shit and dont want to give bad info and I dont like giving electrical advice via the interwebz for the obvious reasons like I dont want to burn someone's house down because I was stoned and felt like playing Mr. KnowitallElectrician.
Boy digging this book out was a blast from the past.
Im not sure why its all in Celsius but here is the table typed out(all Celsius)
21-25 1.08
26-30 1.00(the table is based on this temp)
31-35 0.91
36-40 0.82
41-45 0.71
46-50 0.58
51-55 0.41
56-60 ------
61-70 ------
So say it could get up to 34 Celsius, then 40 amps X .91 =36.4 meaning 8 gauge wire would be rated at 36.4 amps at those temperatures
Fwiw guys Im a currently laid off for the summer industrial electrician but I havent wired anything residential in 5+ years and my job doesnt require much wiring, more troubleshooting motor controls and working on PLC's so I been reading this thread interested but not really wanting to get involved, for one Im rusty with this shit and dont want to give bad info and I dont like giving electrical advice via the interwebz for the obvious reasons like I dont want to burn someone's house down because I was stoned and felt like playing Mr. KnowitallElectrician.
Boy digging this book out was a blast from the past.
W
Whatever
I think I know enough to say if temp correction factors come into play you were running too close to the edge to begin with and didn't leave enough wiggle room.luciano28 said:
G
Guest
What's the big deal with running 10-2? If it was 10-3 he'd have to cap the neutral. All the NEMA 6-20s I've seen are 3 wire self-grounding. Are we talking about future-proofing or what?00420 said:
Johnny Rotten
Member
If you put a meter on the left side of a 240v circuit to ground, black wire, it reads 120v. If you put it on the right side to ground, white wire, it reads 120v. If you put it across both it reads 240v.
Most 240v circuits use a 10-2 and have no neutral, just two hot and a ground.
Most 240v circuits use a 10-2 and have no neutral, just two hot and a ground.
i was to tell i started growing......Whatever said:
honestly bro i have no clue...but my guess this is why we stay at 80% load i can say for 10yr's now i have never had a prob with 10/3 with 4k if i do a room with 4k+ i run a 2nd set or wire & split the load i hope this helps you ...haha the max i would say is 90 anything after that and your plants start to look like shit.... BUT a lot of wiring is in the wall's or out of the grow room where i have seen it up to 115luciano28 said:
i dont like to advise like you for the same reason, but its better the person behind the name besafe then do it wrong and me be sry i did not try
agreewhatever said:
Even_Steven said:
luciano28 is right on the $
the 3 wire you seen how many where bare? ( the self grounding witch ='s 4 )
luciano28 said:
luciano28 said:
Interesting. So riddle me this. How come you can take the connecting clip off the knobs on that breaker and have two 20 amp breakers, or why you can put a clip on two 20 amp breakers and get a 240v breaker? Each side of that breaker is 20 amps. 1/2 your current is passing through one breaker, the other half is passing through the other breaker, isn't it.
Breakers don't pop at 80% of their rating, it is recommended not to exceed 80% of their rating because of surges and such.
PC
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I didnt think I was being a smart ass but Ok. I think if you read your own post a few times you will see the answer. He has 20 amps at 240 and 40 amps at 120 right? What is he using? He isnt using 120, 2 hots run to the breaker with only 1 common equals 240 volts.
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G
Guest
I think it's setup that way to handle the heat that comes with the extra watts of 240v.PharmaCan said:
