Gothic Arch greenhouse

Step 8 : Electricity and Climate Controls

The ventilation fan was installed into the opening at the top of our back wall, and the heater was hung from the pipes shown to the right of this photo.  We used a circular concrete saw to cut two round holes into our floor and then cemented vertical support pipes at these locations.  A horizontal pipe was mounted between them to hang our heater, and two horizontal braces were also added to help support it to the back wall.  

the ventilation fan and heater controls

This upper photo also shows the electrical work in progress.  The heating and ventilation systems are on two different circuits and were both wired into switch boxes.  The switch boxes were mounted up high so that they can not be accidentally turned off, but are available as a safety feature when maintenance is required.  The ventilation fan has a two stage motor and was wired to a climate controller with min/max settings.  When the greenhouse temperature rises to a certain temperature, it will turn on at the slower speed and open the largest louver on our front wall.  If the temperature in the greenhouse still rises up to the higher temperature, the fan speed will then increase and the second louver on our front wall will be opened.    

the circulation fan and electrical boxes

At opposite corners of the greenhouse we installed circulation fans.  These fans were wired onto a separate circuit so that the fan speed can be adjusted using a dimmer switch.  Along the side walls were located numerous electrical boxes with water resistant covers.  As seen here, all wiring was run through electrical conduit using waterproof connections.  

The bending of conduit and wiring was not a simple task but we were fortunate to find an experienced electrician to help us with this portion of the construction.  Because of the variety of fans, vents, heaters and various methods of controlling them, the electrical work required careful planning to ensure that all items worked properly and that the circuits were not overloaded.  

Colored wires of the proper gauges were installed through the waterproof conduits as needed to connect the greenhouse systems to the circuit panel.  As each circuit was wired, it was labeled and tied off at the electrical panel until final connections were made to the correct size circuit breakers.

The majority of controls were attached adjacent to our circuit panel.  In the bottom photo can be seen the dimmer control for our circulation fans, the min/max climate control for our ventilation system, the temperature control for an alarm system and the humidistat for the under bench misting system.

the electrical box and maze of wires

the finished circuit panel and controls

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