Marijuana growers have historically been very hard on breaker panels, transformers and wiring, but there is a huge range of cultivators’ sophistication as it relates to electrical power.
As a specialist in low-voltage circuit protection, I want to preface this by saying that I think most cultivators are using power safely, and there are probably only a few folks who need to change what they are doing. But this article was inspired from something I heard over a round of beers one night, when I was introduced to an engineer-turned-grow-op-power-consultant (which is not too farfetched of a title to find in Colorado). He delighted in telling me how he was advising a fairly large grow operation, and that they were “maxing out” 400-amp circuit breaker panels. He mentioned how often breakers would trip because they ran hot, so they blew fans on the panels 24/7 to keep them cool.
This is entirely the wrong way to do it, and it deeply disturbed me. The account of electrical panel over-clocking made me wonder: How pervasive is this issue? I haven’t done the research to know, but it did illuminate the fact that growers are not like regular users of electricity. Their loads are (almost) always on, and they are extremely uniform. They use huge lamps that dissipate tons of heat — so much that they also require banks of fans.
Recommendations
In short, a modern grow-op resembles the Byzantine arms of Dr. Octavius, snaking through a maze of data center wiring, pulsating with the energy of an electronic dance music festival. Given the complexities, electrical power for these facilities requires more thoughtful planning than the do-it-yourself and piecemeal approach. Competition will inevitably weed out the truly unprofessional, but for those who are merely unaware or are just waiting to get around to it, I am here to recommend that you make sure your electrical operations are in order.
Here are some basic recommendations for a solid power plan:
– DO hire professional engineers and electrical contractors, and ensure that all work is inspected before commissioning your facility.
– DO think out your actual, total power needs before installing anything. How many lamps, fans, pumps? At what voltage? Keep in mind that higher voltage results in lower resistive losses in your equipment and will reduce your cooling demands slightly.
– DO consider the power factor of your facility. Power factor is the ratio of the real power (that which the equipment can use) to the apparent or total power, which is the combination of the usable (real) and unusable (reactive) power. If your power factor is unacceptably low, you will be at risk of a surcharge from your utility, and your equipment losses will be much greater. Poor power factor may also cause unintended heating in your equipment. Special equipment that adjusts your building’s power factor, either fixed or dynamically, can greatly improve energy efficiency and reduce your overall energy costs.
– DO consider the thermal performance of the building. This could require a trained energy analyst who can identify your actual heating and cooling loads in order to determine the size of the equipment you’ll need. The heating and cooling loads and the power demands on the building are interrelated; if you dissipate more heat in your power system, you’ll need to find a way to remove it from your facility. Conversely, the larger your air-handling equipment, the more power it uses.
– DO consider the thermal performance of your electrical equipment. Transformers have been designed to last for decades and can accept a very large temperature rise inside their core (often rated +150 degrees Celsius or more). Transformers may handle abuse much better than other equipment. Still, it is not recommended, and in any case, it can be expected that the life of your equipment will be affected adversely if it runs hot. In the electronics world, it is understood that the reliability drops by half for every 10 degrees Celsius the temperature increases. Plan accordingly.
– DO NOT push the limits of your equipment. The ratings on the equipment are the absolute maximums. A 400-amp panelboard means 400 amps! Therefore, 400 amps is the maximum amount it can handle while remaining safe in lab-testing conditions. If it runs above that limit, someone could burn themselves on the equipment, it probably won’t work properly, and it could even catch fire.
For your circuit breaker panels (panelboards), it is wise to oversize the equipment. You can buy a panel with a 400-amp busbar for use in a 200-amp system. You can buy a larger enclosure, then alternate the breakers with empty space to ensure the breakers run cooler, with fewer hot-spots. You can also buy purpose-built, ventilated control panels for additional peace of mind.
An electrical engineer inspects the circuit breakers at a grow facility in Washington. Photo by Gary Delp.
Keep it Cool
Just as a reminder, here is what happens when electrical equipment runs too hot:
– It does not perform reliably. Breakers nuisance trip or open for apparently no reason. Unintentional tripping of breakers causes expensive downtime, but also affects their calibration. They are less accurate the more times they trip. Also, when a breaker runs hot, its current-handling limit is reduced, to the tune of about 1% per degree Celsius (relative to their 40 degrees Celsius calibration temperature).
– High heat means the equipment degrades more quickly. Insulating properties of materials and plastics can become compromised. This reduces the equipment’s ability to handle the voltage for which it is rated, which could cause arcing, or even a flashover or arc blast — all of which are exceptionally destructive and potentially lethal.
– Wire connections are thoroughly stressed. Failing terminals on breakers, lugs or other wiring connections is the leading cause of damage inside electrical equipment. Glowing connections can burn through metal and ignite other materials.
– Wire insulation can become brittle and crack, which can pose both a shock and a fire hazard. One of the most dangerous things you can do is run wiring too small for the current.
Trip-free breakers
There was a time when people could hold the handles of breakers in an ON position, in order to prevent the circuit from tripping. This technique may have proved useful in a grow house with a small electrical panel pushed to the brink, but it is extremely dangerous, because it overrides the protection feature of the circuit breaker — its sole reason for existing in the first place.
Fortunately, most cultivation professionals are above such dicey means — and even if they were not, holding the breaker paddle down is no longer possible. UL 489, the UL standard for circuit breakers, requires mechanical, trip-free operation, which means that an operation to “trip” takes precedent over the mechanical position of the breaker paddle. This prevents the unwary user from closing the breaker into a faulted or damaged circuit and also prevents abuse such as deliberately overriding the trip feature of the breaker by holding the paddle down. Using a UL 489-listed breaker protects you and your business from this type of misuse.
To wrap it all up: Be kind to your electrical equipment. While mostly unappreciated, it is there to serve you and your business and to protect you. With the same love and care you give your plants, the equipment will repay you in reliable service and a thriving business.
David White is the CEO of Tenmile Labs and a specialist in low-voltage circuit protection devices and equipment. He is a professional power engineer in California with nearly a decade of experience designing solar power systems and industrial equipment.