Greenhouse

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aftershock

aftershock

Senior Member
Location
Memphis, TN
My boss had me go move a panel that was obstructed by a new greenhouse that has been built.
While I am to be there doing this, my boss wants a material list on what we will need to wire the electrical in this greenhouse.
It has:
1 htr unit @220/v 54 amps
2 ac units? @110/v 7.3 amps each
2 actuators<sp> @110/v .25 amps each
1 fan, I guess to just keep air circulating and since I did not check the amps, I can only guess about 3 amps.
Customer will want about 3 quad receps and one other switched recep for rope lighting.
Customer wants me to use pvc for my conduit.

Customer has all the equipment on site except the rope lighting which I guess he will just plug in and run it how he wants.
There will be 5 high voltage thermostats to control the htr, ac, ac, actuator, actuator.


I have never wired a greenhouse, I have only done service calls on one and replaced things. I pretty much know how everything is going to work, I just have a hard time coming up with a material list because this seems to be one of those "make it up as you go along" because I dont know what I am going to run into trying to feed all 5 pieces of equipment from 5 different thermostats until I start working with it.

First problem I see is: All the thermostats break only 1 leg. This is fine for anything running at 110/v but I have a feeling I will need the thermostat for the 220/v heater to control a 2 pole contactor instaed of going straight to the heater. I will also need a means of diconnect within sight unless I can use something to lock the breaker in the open position.

2nd problem. Customer wants me to cut the cord caps off of the ac units. I dont think I should do this. I know he wants to save money by not having another opening charged to the job, but even if I could get away with hardwiring these 2 units in,, I would have to have a 20 amp switch as a means of diconnect.

3rd problem. Customer wants pvc to reduce the cost of materials. I remember reading another thread (cant find it now) where someone posted that pvc is not good in a greenhouse environment due to chemicals?
Plus , unlike using emt, I will have to have prefab 90's and 45's and knowing how many I could possibly need is hard to determine.

4th problem being my boss. He wants to get this material list in so he can give a price and thus get us some work because we are at a dead stop. Other than the knowns, all I can write up is like, a box of this fitting, that fitting, 100' of this pipe and a spool each of hot, neutal and ground #12 thhn.

Im an installer Jim, not an estimator.

Any do's dont's and suggestions as far as type of material to use would be helpful in figuring out what to list and what to explain to the customer as to why we need to do it this, or that way.

Pictures attached
 
Rick, is that 220v heater 54 amps or 5.4 amps?

The PVC might be due to the high humidity in the greenhouse - I would imagine that emt would start to rust fast.
 
JohnJ0906 said:
Rick, is that 220v heater 54 amps or 5.4 amps?

The PVC might be due to the high humidity in the greenhouse - I would imagine that emt would start to rust fast.
Click to expand...

Htr is 54 amps with a 60 amp Max fuse.
I double checked it. It seemed hard to believe something that small had that much of a heating element. But I can dbl check tomorrow since I need to return to finish the panel move.
 
I'd done exactly two greenhouses, and those things have way more controls than I ever dreamed of. They're pretty complex, actually. Controls to open and close the roof sections, turn fans on and off, turn heat on and off, turn water mist on and off. Lots of timers. Lots and lots of sensors to pipe in. All PVC, lots of FSE boxes, etc. Not too much THHN involved, but a good bit of UTP and thermostat wire. Without breaking out instruction booklets, just assume that each piece that you wire up will have a sensor or timer associated with it, and see what you can do from there. Honestly, I'd try real hard to get the first greenhouse you do as T&M to get some historical data on how they go. Plan on having a hot box on the job, because the way these things are built, factory 90's just don't do the trick.
 
mdshunk said:
I'd done exactly two greenhouses, and those things have way more controls than I ever dreamed of. They're pretty complex, actually. Controls to open and close the roof sections, turn fans on and off, turn heat on and off, turn water mist on and off. Lots of timers. Lots and lots of sensors to pipe in. All PVC, lots of FSE boxes, etc. Not too much THHN involved, but a good bit of UTP and thermostat wire. Without breaking out instruction booklets, just assume that each piece that you wire up will have a sensor or timer associated with it, and see what you can do from there. Honestly, I'd try real hard to get the first greenhouse you do as T&M to get some historical data on how they go. Plan on having a hot box on the job, because the way these things are built, factory 90's just don't do the trick.
Click to expand...

I agree with Marc completely. I have wired three(more than Marc, sweet:D) and they were all completely automated with temp. controls, photocells, air movement sensors. All pvc, lots of utp.
We definately lost some money on the first one...BIG wakeup call
 
You need to have a plan before you start piping this project anyways, so it should be easy to get a material list.
If you don't have a plan with a large exposed pipe project it's going to look like... crap... And that isn't what you are going for here.
Sure you might need an extra coupling here and there but for the most part you should have a very good visual about how all of the conduit is going to tie into the larger electrical system of the building before you even lay your first piece of it.
Specs and instructions an all of the equipment is very necessary, you don't want to end up finding yourself short a conduit opening where you need one, or find yourself out of wire counts inside the pipe you do run.

The 2nd problem you mentioned is not a problem- You are right- either way it's an opening because you need a disconnect of some type- either a switch or a receptacle- I would highly recommend doing the receptacle because then he can 'hook them up' himself rather than the boss charing him more for the time it took for you to hook it up by tying it in for him, and as a recepacle then it is owner maintanance friendly.

But as I mentioned above- to reitterate- you need a very good plan for your conduit runs before you ever lay your first piece of pipe anyways so coming up with a material list should be easy. Draw it out if you have to. If its all coming off the same electrical source you might find yourself needing only a couple long runs that you can branch off of with T's or whatever whenever you have an opening you need to connect to for either control or actual equipment hook up.
 
green houses

green houses

I have done a couple of greenhouses. Emt was speced on the ones I wired. The panel(s) were at one end othe structure away from the "watering" areas. There was a main control panel for the house that all the remote sensors were landed at. The company that built the houses was the same outfit that builds a lot of the houses for Walmart garden centers. As Marc stated, the electrical is easy,most of your time is in the controls..exhaust, heat etc,etc.
 
Oh, sun shades too. The one's I did had shades under the roof sections that would vary their position, depending on some hocus-pocus that the sensors were doing.
 
aftershock said:
3rd problem. Customer wants pvc to reduce the cost of materials. I remember reading another thread (cant find it now) where someone posted that pvc is not good in a greenhouse environment due to chemicals?
Plus , unlike using emt, I will have to have prefab 90's and 45's and knowing how many I could possibly need is hard to determine.
Click to expand...

I have had success with using a spring that slips inside the pvc for making bends that might help
 
ctmike said:
I have had success with using a spring that slips inside the pvc for making bends that might help
Click to expand...
The Piper Viper is okay, but you have to seriously overbend, and the actual degree of the relaxed bend is hard to determine. Getting two exactly alike is a real trick, and getting bends for an offset sufficiently close together to look right is pretty tough. Don't get me wrong, it's useful enough to be on a service truck, but if I had to do a whole PVC job with one, it would drive me nuts. The small hot box is not too much money if you don't own one, and a decent sized PVC job is excuse enough to buy one.
 
I ran into a problem today when I was hooking up the heater.
It seems this heater also requires a 220/v thermostat. I should have researched this more or opened the access cover to the heater sooner.
Whichever company supplied this customer the parts/equipment to do this, supplied 5 single pole line voltage thermostats. Or shall I say, you have 1 common and 2 S/L's. 1 S/L that closes when temp rises and the other opens when temp rises.

I will include the wiring diagram of the heater, It does not seem to have taken a clear picture. Is there a way to bypass the use of a 220/v thermostat? Is there a way to use the thermostat that was supplied?

The way I have it set up now is: common hits the common on the thermostat and a S/L from the point where it closes when the temp rises which goes to the coil of a 60 amp contactor. From the contactor it hits the heater.

Did I mention I have never wired a greenhouse before?
 
Take your time estimating. One piece at a time,list material and time you exspect. Never worry about the total and do consider the climate you will be working in. Labor usually will be more than exspected and seldom less.
 
aftershock said:
I ran into a problem today when I was hooking up the heater.
It seems this heater also requires a 220/v thermostat. I should have researched this more or opened the access cover to the heater sooner.
Whichever company supplied this customer the parts/equipment to do this, supplied 5 single pole line voltage thermostats. Or shall I say, you have 1 common and 2 S/L's. 1 S/L that closes when temp rises and the other opens when temp rises.

I will include the wiring diagram of the heater, It does not seem to have taken a clear picture. Is there a way to bypass the use of a 220/v thermostat? Is there a way to use the thermostat that was supplied?

The way I have it set up now is: common hits the common on the thermostat and a S/L from the point where it closes when the temp rises which goes to the coil of a 60 amp contactor. From the contactor it hits the heater.

Did I mention I have never wired a greenhouse before?
Click to expand...

The thermostat could possibly only be breaking on leg of the 240v.
 
walkerj said:
The thermostat could possibly only be breaking on leg of the 240v.
Click to expand...
I wish I had a clearer pic of the diagram but I checked and I was getting 240/v at the contact point for the thermostat wires and this was coming from the line voltage.

So I know that when/if I do wire in a 240/v thermostat to this point,, I need to make sure I dont cross phases.

I wish there was a way I could bypass that and use the method I have wired already.
 
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