Electrical Question: Is setup good or will length and thickness of cable cause voltage drop?

Sam&Max

Sam&Max

Active Member
Hi,
I want to know If with my setup my lamps will run at full power or if my electrical installation will be inefficent.

Ok my setup:
I have four 750W Double ended lamp fixtures.

My plan was to put two lamps at one circuit. That would mean two circuits for all four lamps.

I have 16 amp breakers and 220 volts. (On circuit would be technically strong enough for 3520 Watts?)
The cables are equivalent to 16 AWG or 1,5mm^2 in metric.

The length of the cables to the lamp fixtures (including the length of the cables of the lamps ballast itself) would be... I guess... maximum 20 meters.

Now the problem I worry about:
I did read, if the cable is too long and/or the cable to thin, you would get a voltage drop. I did read that a voltage drop of 10 % causes the lamp to work only at 70% (I am not sure if I remember this piece of information technically correct, but I understood that a voltage drop would be pretty bad)

So now my question:
At what length of cable and thickness I have to expect a drop in voltage? (I have 220volts)
Do I need to install 14 AWG cables instead?
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Sam&Max said:
Hi,
I want to know If with my setup my lamps will run at full power or if my electrical installation will be inefficent.

Ok my setup:
I have four 750W Double ended lamp fixtures.

My plan was to put two lamps at one circuit. That would mean two circuits for all four lamps.

I have 16 amp breakers and 220 volts. (On circuit would be technically strong enough for 3520 Watts?)
The cables are equivalent to 16 AWG or 1,5mm^2 in metric.

The length of the cables to the lamp fixtures (including the length of the cables of the lamps ballast itself) would be... I guess... maximum 20 meters.

Now the problem I worry about:
I did read, if the cable is too long and/or the cable to thin, you would get a voltage drop. I did read that a voltage drop of 10 % causes the lamp to work only at 70% (I am not sure if I remember this piece of information technically correct, but I understood that a voltage drop would be pretty bad)

So now my question:
At what length of cable and thickness I have to expect a drop in voltage? (I have 220volts)
Do I need to install 14 AWG cables instead?
Click to expand...
There are charts that are pretty easy to find online that show the necessary gauge wire for what ever combination of amperage/voltage/distance. You should be able to reverse it to find the maximum distance for your gauge of wire. Odds are though that as long as you're using digital ballasts you could use any single OEM cord and be fine.
 
Sam&Max

Sam&Max

Active Member
What do you mean,when saying when using digital ballasts you could use any single OEM cord and be fine? Can you please explain your reasoning?

For calculation I googled quickly and I did use this here:
http://www.paigewire.com/pumpWireCalc.aspx?AspxAutoDetectCookieSupport=1

For 240 Volts (not 220 :-/ which would mean less distance) it says I can use 59 feet of cable with AWG 16 for a 3% voltage drop maximum. If I go to 60 Meters, I need to use AWG 14 for voltage drop of 3 %.

Can anyone with experience tell me what a 3% of voltage drop translates into, performance wise of my lamps? Will my lamps run with less brigther light, or will they run at the same strength and just pull more electritiy?
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Sam&Max said:
What do you mean,when saying when using digital ballasts you could use any single OEM cord and be fine? Can you please explain your reasoning?

For calculation I googled quickly and I did use this here:
http://www.paigewire.com/pumpWireCalc.aspx?AspxAutoDetectCookieSupport=1

For 240 Volts (not 220 :-/ which would mean less distance) it says I can use 59 feet of cable with AWG 16 for a 3% voltage drop maximum. If I go to 60 Meters, I need to use AWG 14 for voltage drop of 3 %.

Can anyone with experience tell me what a 3% of voltage drop translates into, performance wise of my lamps? Will my lamps run with less brigther light, or will they run at the same strength and just pull more electritiy?
Click to expand...
Any good digital ballast uses feedback adjust power to the bulb so they can edge timely power lights from farther away than magnetic ballasts. There are long range igniters for magnetic ballasts that will let them start a bulb from further away but the ballasts won't adjust power to the bulb like a digital ballast.

You can get longer than normal lamp cords. Companies wouldn't those cords of they didn't work right with their ballasts. I wasn't sure if my use of the "single" might have been confusing in my first post. What I meant was using just one. I've seen some extension cords for ballasts and figured that someone could get into trouble trying to put to many extensions cords together.
 
Sam&Max

Sam&Max

Active Member
Ok. It is not about the length of the OEM cable. I think if the ballast works properly with the OEM cable, depends on the length of the cable of the whole circuit.

So it seems that my 16 AWG has something around a 3% of voltage drop.

But you mean I don't need to put a new 14 AWG circuit in place because the digital ballast can somehow adjust?
 
F

Fubard

Well-Known Member
Sam&Max said:
Hi,
I want to know If with my setup my lamps will run at full power or if my electrical installation will be inefficent.

Ok my setup:
I have four 750W Double ended lamp fixtures.

My plan was to put two lamps at one circuit. That would mean two circuits for all four lamps.

I have 16 amp breakers and 220 volts. (On circuit would be technically strong enough for 3520 Watts?)
The cables are equivalent to 16 AWG or 1,5mm^2 in metric.

The length of the cables to the lamp fixtures (including the length of the cables of the lamps ballast itself) would be... I guess... maximum 20 meters.

Now the problem I worry about:
I did read, if the cable is too long and/or the cable to thin, you would get a voltage drop. I did read that a voltage drop of 10 % causes the lamp to work only at 70% (I am not sure if I remember this piece of information technically correct, but I understood that a voltage drop would be pretty bad)

So now my question:
At what length of cable and thickness I have to expect a drop in voltage? (I have 220volts)
Do I need to install 14 AWG cables instead?
Click to expand...
I know that we used to run 24vdc for outdoor lights with 0.75mm² with a maximum distance of 30m before the drop could become an issue, the reality was we could have made 50m


Will look for a voltage drop calculator, could help others, but personally I'd think about upgrading to a 2.5 purely because of ambient temperature and the load being up near the limit for 1.5, but that's me.

So, the biggest one is load and distance. According to https://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html , you can easily do 20m with 1.5 and have a voltage drop of 3.8%, well within requirements at an ambient temperature of 30 centigrade. As the temperature rises, you need to upgrade to 2.5 if that hits 50 degrees, which should not happen when growing as the plants won't like that.

So for what you say you needed 1.5 is enough, but I would up it to 2.5 purely because of the load.
 
Sam&Max

Sam&Max

Active Member
Thank you very much!

What does a voltage drop of 3.8 % mean for the perfomance of my lamps?

What do you mean when you say, that you would up to 2.5 purely because of the load? I will run on one circuit two lights, which equals 1500 Watts. Technically the circuit would be able to do more than 3000Watts.

And maybe you have an answer to another question... I need to time some solenoids, so i would need reliable digital time switches. Reliable in the sense that they don't get a time drift with time, because the I need to use them synchronized with the other time switches. Reliable also in the sense that they don't just fail. Digital, because it seems you can set the digital ones by minutes, but the analog ones only by quarter hours). Do you know any good time switches?
 
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SchmoeJoe

SchmoeJoe

Well-Known Member
Sam&Max said:
Ok. It is not about the length of the OEM cable. I think if the ballast works properly with the OEM cable, depends on the length of the cable of the whole circuit.

So it seems that my 16 AWG has something around a 3% of voltage drop.

But you mean I don't need to put a new 14 AWG circuit in place because the digital ballast can somehow adjust?
Click to expand...
The whole circuit isn't the issue. The lamp cord between the ballast and bulb is. The ballast will function properly at the full 220-240 range so as long as you use the right cable to run to your ballast based on distance and just place the ballast where the standard lamp cord reaches with enough slack you're golden. It's really that simple.
 
Cold$moke

Cold$moke

Well-Known Member
Are you running gavitas?

I only ask
becuase i originally designed my room for 4 and now im using 1 and might add 1more mabey lol
But 4 would be insane in my 8x8 room :)
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Cold$moke said:
Are you running gavitas?

I only ask
becuase i originally designed my room for 4 and now im using 1 and might add 1more mabey lol
But 4 would be insane in my 8x8 room :)
Click to expand...
4 at 600 would probably be just about perfect. 4 at 750 would probably be about right in a sealed room with co2.
 
Sam&Max

Sam&Max

Active Member
@SchmoeJoe Ok. That is awesome. I will run the ballasts directly at the lamps without a cord. Why isn't voltage drop an issue on the whole circuit? Because digital ballasts adjust? I have not much clue about electricity :-D

@Cold$moke I will use adjust a wings 600 to 750 Watts. I was thinking about gavitas, but didn't like the light footprint...
How many watts are you using?
 
OzCocoLoco

OzCocoLoco

Well-Known Member
SchmoeJoe said:
The whole circuit isn't the issue. The lamp cord between the ballast and bulb is. The ballast will function properly at the full 220-240 range so as long as you use the right cable to run to your ballast based on distance and just place the ballast where the standard lamp cord reaches with enough slack you're golden. It's really that simple.
Click to expand...
:clap:
 
Cold$moke

Cold$moke

Well-Known Member
SchmoeJoe said:
4 at 600 would probably be just about perfect. 4 at 750 would probably be about right in a sealed room with co2.
Click to expand...
I was asking the OP

Cause if you dont have ceiling height gavitas are pretty crazy and will burn or bleach a plant pretty bad.

Thats why i designed my room FOR 4 and now im only using 1 in a 8x8 and i might add 1 more

But 4 would be crazy and i would have to run ac or co2 which i dont want the ac. But i will add co2 at a later time
 
Cold$moke

Cold$moke

Well-Known Member
[USER=889071 said:
@Cold$moke[/USER] I will use adjust a wings 600 to 750 Watts. I was thinking about gavitas, but didn't like the light footprint...
How many watts are you using?
Click to expand...
I dont know what your conditions are like.

But i am using 1 gavita 750 set at 600w (right now) for about a 8x8 its crazy bright and fills the whole room.

THE ONLY reason i would add 1 more is if my yeilds suffer .

But so far it is kicking ass but im not in flower yet :)

Edit to add. It looks good on paper to run 4 gavis
But i would probably be bleaching ALL. My plants if i had 4.
Im scared of what 2 will do lol
 
Sam&Max

Sam&Max

Active Member
yes the reflector sends the light pretty wide... that is what i didn't like. I have four 4x4 tables in a row. So almost like you. I will put a 600 to 750 Watt lamp over each table. So four lamps. I will use CO2 too. My ceiling will be good for the adjustaWings and would be good for 750WGavitas too. But the adjustawings seem to have a better reflector for smaller grow rooms. Also you can hang them lower without burning your leaves.

I am doubting a bit that one 750W gavita is enough for an 8x8 setup. :/
 
Cold$moke

Cold$moke

Well-Known Member
I will post my results in 2 monthes.
For 1 gavita over 8 plants in rdwc.

If it beats my old set up i will have used half the power this is why they where worth it to me :)
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Cold$moke said:
I was asking the OP

Cause if you dont have ceiling height gavitas are pretty crazy and will burn or bleach a plant pretty bad.

Thats why i designed my room FOR 4 and now im only using 1 in a 8x8 and i might add 1 more

But 4 would be crazy and i would have to run ac or co2 which i dont want the ac. But i will add co2 at a later time
Click to expand...
Ok, it seemed like a general question. As far as the gavitas go a big part of the reason they need so much hight, other than heat, is that they have an extremely uneven coverage area and you need the extra distance to take advantage of the inverse square proportion law to help spread out the hot spot.

Do a Google search for "best grow light reflector" and look for the side by side comparison done by Growers House. It definitely deserves a read through by anyone that ever thinks about what hid system to run and coverage areas.
 
Cold$moke

Cold$moke

Well-Known Member
Wings are badass too dont get me wrong
I was just giving my exp.

Going from 1500 watts that barely lit the room (reflector sucked too)

And the 1 gavita the bulb is at 8 ft and it is lighting the whole room much better
Although i dont have a par meter so im basing it off the old eyeball :)
 
Cold$moke

Cold$moke

Well-Known Member
SchmoeJoe said:
Ok, it seemed like a general question. As far as the gavitas go a big part of the reason they need so much hight, other than heat, is that they have an extremely uneven coverage area and you need the extra distance to take advantage of the inverse square proportion law to help spread out the hot spot.

Do a Google search for "best grow light reflector" and look for the side by side comparison done by Growers House. It definitely deserves a read through by anyone that ever thinks about what hid system to run and coverage areas.
Click to expand...
Sorry if i came off as rude
Was just asking the op which DE he went with :)

I believe you im not stating you are wrong

But so far SO GOOD AND IF I CAN GO FROM 1500w TO 750w with a max of 825.w on boost

I will be extremely happy and if i equal my old power output i know they will kick my old set ups ass.

My 8x8 is lit VERY evenly but its only to my eye like i said. No par meter

Who knows in 2 months if i dont get at least 2 lb off it i will know lol. But so far i think ill hit my goals mabey better.

My dream goal is to hit 4 lb in 8x8 with as little as possible if i can get close ill be happy :)
 
SchmoeJoe

SchmoeJoe

Well-Known Member
Cold$moke said:
Sorry if i came off as rude
Was just asking the op which DE he went with :)

I believe you im not stating you are wrong

But so far SO GOOD AND IF I CAN GO FROM 1500w TO 750w with a max of 825.w on boost

I will be extremely happy and if i equal my old power output i know they will kick my old set ups ass.

My 8x8 is lit VERY evenly but its only to my eye like i said. No par meter

Who knows in 2 months if i dont get at least 2 lb off it i will know lol. But so far i think ill hit my goals mabey better.

My dream goal is to hit 4 lb in 8x8 with as little as possible if i can get close ill be happy :)
Click to expand...
No problem, you're good. I couldn't find the side by side I was talking about so i dug through their reviews and comparisons and couldn't find it. It's actually weird because it was all still current equipment and their biggest comparison with, I think, ten hoods while they have others with just 2 or 3.

Anyway not to threadjack, I just wanted to try to contribute where I could.
 
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