200 amp 3 phase 208 volt service

[Jcomeaux21]

I have a 5 50 amp lighting control boxes that control 8 1000w mh light a piece. Each ballat is 4.8 amps if I did this correctly 4.8 x 40=192 . Would that be devided between all 3 legs and be 64 amps per leg? If so, do I still have space in my panel for more applications?

 

[iwire]

A 200 amp 208 volt three phase service can supply just under 72,000 watts non continuos.

Expanding the grow room?

 

[JFletcher]

Welcome. The loading of the panel is going to depend on what phases the loads are on. You have 3 phases and 5 208V L-L loads. How they are split now, who knows. P=VIsqrt3 so you have more like 110A per leg, assuming a balanced load that is impossible to achieve with the configuration you have now (unless they are 3ph lighting control boxes).

Get an amp clamp/ammeter and measure your loads.

 

[infinity]

I have a 5 50 amp lighting control boxes that control 8 1000w mh light a piece. Each ballat is 4.8 amps if I did this correctly 4.8 x 40=192 . Would that be devided between all 3 legs and be 64 amps per leg? If so, do I still have space in my panel for more applications?

Are these all 120 volts?

 

[dkidd]

Are these all 120 volts?

It looks like 208 volts from the data he posted, but that must not be actual nameplate values.

 

[kwired]

Are these all 120 volts?

Those are some pretty efficient units if they only draw 4.8 amps at 120 volts, If 100% PF it comes out nearly right where it should for 208 volts, but they are never that efficient - so my guess is that is the 240 volt or even 277 volt nameplate amps.

 

[kwired]

I have a 5 50 amp lighting control boxes that control 8 1000w mh light a piece. Each ballat is 4.8 amps if I did this correctly 4.8 x 40=192 . Would that be devided between all 3 legs and be 64 amps per leg? If so, do I still have space in my panel for more applications?

Power calculations on balanced portions of three phase loads involves use of the square root of three in the calculations because of the phase angles of the applied voltage.

Clamp an ammeter on your lines and I bet you see nearly double the amps you came up with your calculation method.

Since you don't have equal number of units on each phase in each circuit you don't have balance across the phases, and will have one leg per circuit that draws less current then the other two, but you can compensate some for the entire feeder/service because you have multiple unbalanced circuits.

 

[Dennis Alwon]

1000/208= 4.8 but this is mh so isn't there a pf to consider. I find it hard to believe the ballast is 4.8 amps

 

[kwired]

1000/208= 4.8 but this is mh so isn't there a pf to consider. I find it hard to believe the ballast is 4.8 amps

But it might be about right for 240 volts after considering power factor. Unless I calculated wrong that would be about a 87% power factor if 4.8 A is the current rating for a 1000 watt load.

 

[iwire]

Darn it folks, do we have to make every thread complicated? :blink: 4.8 is in the ball park.

Here is a 1000 watt, MH, pulse start ballast it shows 4.7 amps at 240 volts and 5.6 at 208. https://www.grainger.com/product/PHILIPS-ADVANCE-Metal-Halide-HID-Ballast-Kit-6CAU1


As far balancing etc, why not wait till the OP asks for more info?

 

[dkidd]

Darn it folks, do we have to make every thread complicated? :blink: 4.8 is in the ball park.

Here is a 1000 watt, MH, pulse start ballast it shows 4.7 amps at 240 volts and 5.6 at 208. https://www.grainger.com/product/PHILIPS-ADVANCE-Metal-Halide-HID-Ballast-Kit-6CAU1


As far balancing etc, why not wait till the OP asks for more info?

He does say it is 208.

 

[iwire]

He does say it is 208.

So what?

How about letting the OP respond instead of playing guessing games?

 

[Jcomeaux21]

Power calculations on balanced portions of three phase loads involves use of the square root of three in the calculations because of the phase angles of the applied voltage.

Clamp an ammeter on your lines and I bet you see nearly double the amps you came up with your calculation method.

Since you don't have equal number of units on each phase in each circuit you don't have balance across the phases, and will have one leg per circuit that draws less current then the other two, but you can compensate some for the entire feeder/service because you have multiple unbalanced circuits.

34.4
34.4
33.4 with 22 running along with 5 ton ac and 2.5 ton ac along with other 120v

 

[Jcomeaux21]

208 3 phase

 

[Jcomeaux21]

Darn it folks, do we have to make every thread complicated? :blink: 4.8 is in the ball park.

Here is a 1000 watt, MH, pulse start ballast it shows 4.7 amps at 240 volts and 5.6 at 208. https://www.grainger.com/product/PHILIPS-ADVANCE-Metal-Halide-HID-Ballast-Kit-6CAU1


As far balancing etc, why not wait till the OP asks for more info?

I have a good ballance mainly wondering if I can double what I have 22 lights along with 5 ton ac 2.5 ac and multiple 120 volt fans running st the same time pulling 34.4 34.4 33.4

 

[Besoeker]

I have a 5 50 amp lighting control boxes that control 8 1000w mh light a piece. Each ballat is 4.8 amps if I did this correctly 4.8 x 40=192 . Would that be devided between all 3 legs and be 64 amps per leg? If so, do I still have space in my panel for more applications?

Can you post a pic of the nameplate/label on one of the lights?

My posts keep being disappeared...

 

[JFletcher]

I have a good ballance mainly wondering if I can double what I have 22 lights along with 5 ton ac 2.5 ac and multiple 120 volt fans running st the same time pulling 34.4 34.4 33.4

as iwire stated, a 208V 200A service is good for ~72,050W; 208V x 200A x 1.732 (the square root of 3). 40 1000W HPS lights is already 40,000W, or 111+A (assuming incorrectly a power factor of 1) per phase, so no, you cant double the loading even if it's perfectly balanced. Where are you getting 34.4A from?

 

[dkidd]

I have a 5 50 amp lighting control boxes that control 8 1000w mh light a piece. Each ballat is 4.8 amps if I did this correctly 4.8 x 40=192 . Would that be devided between all 3 legs and be 64 amps per leg? If so, do I still have space in my panel for more applications?

5 boxes x 8 luminaires x 1000 watts = 40,000 watts

Assume 90% power factor and 92% ballast efficiency

Gives 48,309 va

At 208, if balanced would be 134 amps per phase (48,309/(208xsqrt3))

Given a 200 amp panel, assume continuous loading, you have 160 amps capacity.

Therefore, you have 26 amps 3 phase 208 available for additional continuous loads.

 

[Jcomeaux21]

as iwire stated, a 208V 200A service is good for ~72,050W; 208V x 200A x 1.732 (the square root of 3). 40 1000W HPS lights is already 40,000W, or 111+A (assuming incorrectly a power factor of 1) per phase, so no, you cant double the loading even if it's perfectly balanced. Where are you getting 34.4A from?

My amp reading with 22 running along with my ac showed 34.4 per leg

 

[iwire]

5 boxes x 8 luminaires x 1000 watts = 40,000 watts

Assume 90% power factor and 92% ballast efficiency

Gives 48,309 va

At 208, if balanced would be 134 amps per phase (48,309/(208xsqrt3))

Given a 200 amp panel, assume continuous loading, you have 160 amps capacity.

Therefore, you have 26 amps 3 phase 208 available for additional continuous loads.

I am going to point out that if we are really tying to do a calculation that that NEC requires we use the ballast info not the lamp wattage. PF and efficiency do not come into the required calculations.

We can start a new thread about the NEC requirements if we need to.