"Choc" is probably a UK English term. It refers to a plastic terminal very similar to what you have directed me to. A-1 - thanks.
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Growroom Electricity and Wiring
- Thread starter Phillthy
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"Choc" is probably a UK English term. It refers to a plastic terminal very similar to what you have directed me to. A-1 - thanks.
username474
Active member
I just read a story in a newspaper the other day
about a guy causing a brown out in his neighborhood
from using too much electricity for his medical grow. I
am assuming his area was over working their transformer.
Is there anyway to tell before hand if I was pulling around
150 amps that I could cause a similar situation?
Thanks for any insight.
about a guy causing a brown out in his neighborhood
from using too much electricity for his medical grow. I
am assuming his area was over working their transformer.
Is there anyway to tell before hand if I was pulling around
150 amps that I could cause a similar situation?
Thanks for any insight.
There is no way for an end user to determine what the utility transformer loading is. If you are in a neighborhood where they are running pole-top transformers, you could see how many houses are connected to the transformer and perhaps get a vague indication of what the loading might be (empty houses for sale, vacation homes, etc), but that's about it without measuring the load. You might be able to mimic your anticipated load with an electric furnace or some other heavy loading (clothes dryer, oven, etc) but trying to do that for the necessary time period would be a pretty good trick. You could possibly tell the utility that you plan on heavy loads (welder in the shop, pottery kilns, or ??) and ask if their infrastructure can handle it, but that's not as discreet as you would probably like.
RedReign
Active member
In my warehouse I have 3 awg feeding the 480/277 panel. There is a 50 amp breaker on the 480/277 panel with 8 awg going to the primary side of the 75 kva transformer. There is 3 awg from the secondary side of the transformer to the 208/120 panel.
The main electrical room is on the other side of the wall from my 480/277 panel, less than 10' away, so the 3 awg is less than 20' long total. The transformer is 3' away from the 480/277 panel, and the 208/120 panel is also 3' away from the transformer.
I want to replace the 8 awg on the primary side with 3 awg, less than 8' of wire. What size breaker should I use?
What size wire should I use on the secondary side? The 208/120 panel is rated at 200 amps.
The main electrical room is on the other side of the wall from my 480/277 panel, less than 10' away, so the 3 awg is less than 20' long total. The transformer is 3' away from the 480/277 panel, and the 208/120 panel is also 3' away from the transformer.
I want to replace the 8 awg on the primary side with 3 awg, less than 8' of wire. What size breaker should I use?
What size wire should I use on the secondary side? The 208/120 panel is rated at 200 amps.
username474
Active member
Many thanks Rives
It isn't going to do you any good to increase the feeder capacity to the 208/120 panel. The existing 50 amp breaker on the transformer primary is already correctly sized for the capacity of your 208/120 panel - 50 amps of 480v is going to give you 200 amps of 120v.
There is plenty of capacity left on the other components - the maximum current on the 480v primary of a single-phase 75 kva transformer is 156 amps. #3 THHN is rated for 110 amps (other insulations are rated for less). Although both the #3 and the #8 are nominally a bit light, both sound like they are well within the tap rule and should be fine. Is there anything besides transformer primary being fed by the 480/277 panel?
RedReign
Active member
OK, cool. I thought I only had 100 amps of 120v at the 208/120 panel. It's OK to have 200 amps of 120v going through the 3 awg between the 208/120 panel and the transformer?
The only thing besides the transformer fed by the 480/277 panel is (4) 400 watt MH lights. There is one 400 watt MH per 25'x100' section of the warehouse. I need better lighting. What is the most efficient way to light each 25'x100' section? T5's? The warehouse is 20' tall on each end and 26' tall in the center.
I'm currently running 12k in flower and 2.4k in veg, plus AC's, dehueys, fans etc. My normal max demand on my bill is 20kw, but it has been as high as 22kw. I'm currently adding another 12k flower room/2.4k veg room, so I'm guessing my max demand will be in the 44kw range.
Sorry, I screwed up here - a little more research shows that the tap conductor rule was changed in 2011. I think that your installation met the code prior to that time (I'm going off of memory, I would have to dig out my old code books when I get home), but in 2011 they made a change that says that the conductors have to be rated for the overcurrent device that they terminate in. In this case, they would need to be rated for 200a (3/0 wire).
If you are talking about warehouse lighting as opposed to something that gives good color rendition, some 400w HPS industrial lowbay fixtures are probably the best value. Mounting them on 25' centers should give pretty even illumination.
Relays can get pretty warm, particularly in an enclosed area. I don't know if it would be enough heat to melt the glue again, or not. I have seen various components "stuck" onto things with silicone sealants, but I would be nervous about using it with a power relay that has energized components sticking out all over it.
I don't have any direct experience with them, but a quick search shows them to fit. However, they need to be "listed" for the application to conform to code and insurance regulations. The specific breaker model needs to be approved for the specific load center that it is going to be used in to meet approval.
You mean if they fit?
Thanks so much for sharing this. There was a time when I knew this stuff. But my brain is old and covered in mold now.
The receptacles appear to be Nema 6-20R, which is reserved for 240v. The white wires are incorrect for 240v - white wire is only to be used as a neutral for 120v.
I understand. But I am only using pieces of wire.
I should of used a red instead of black but aren't they the same gauge?(all 12)
Just a different color. It will be terminated at one side of the relay.
