Friday, October 16, 2009

More on the Solar Decathlon

At the risk of repeating myself, I want to take a last opportunity to encourage anyone and everyone to visit the Solar Decathlon this weekend on the Mall before it ends on Sunday, October 18th (http://www.solardecathlon.org/).

After two weeks of being back at my regular job, I still am (perhaps over-)impressed by the five days that our group from the JATC spent down there helping out. We brought along our personal tools, two carts full of power tools and a portable generator, and our knowledge from the field and did everything we could to get these teams up and running electrically so that they would be ready to be tied to the grid when the proper time came.

Due to the rush to get their houses completely built and functioning, the students were grateful for our help. As I said in my last post, we did a lot of work with grounding and bonding that was a little bit out of the ordinary. Since these houses were predominantly pre-built and then dismantled, only to be reconstructed once they arrived in Washington, most of the internal wiring was already complete by the time we showed up. That meant that the electrical panels were already wired and were pretty much sitting ready waiting for the meters from the utility.

The contest is special this year because the houses are all tied to the grid. At the last decathlon two years ago, when the JATC brought a class of third-year students down to help out for a day, a lot of the work that our apprentices did was helping out with the bank of batteries used for storage. Our experience was entirely different. Being tied to the grid means that no battery bank is necessary. One category of competition is seeing how much energy each house produces and is able to return to the utility, something that local utilities around the nation pay (or at least credit) private clients for doing. It is a very positive initiative.

As a result of being grid-tied, however, and due to the specifications set up by the contest organizers, each house was required to have a disconnect mounted to the exterior of the house before the feed enters the panel. This disconnect and its connecting raceways requires grounding, of course, and its existence upstream of the panel requires it to be the point of the main bonding-jumper. This was news to a whole lot of people! Understanding grounding and bonding, a very important safety and proper-functioning issue, is part of our course material in the apprenticeship and something you learn in your third year. And understanding the role of the main bonding-jumper and where it needs to be placed is at the heart of the subject!

We therefore had a big job of mounting disconnects and correcting a lot of the grounding systems that the students had installed. We re-pulled feeders and re-landed a lot of the equipment grounds in the house panels. This was all in addition to the work with the PV systems and solar arrays that we were lucky to get involved with!

Our experience made us realize how crucial the work of a knowledgeable electrician is to the developing field of alternative energy. The field is changing every day and is guided by the work of students like those at the competition who are designing practical, beautiful houses like those you can visit down on the Mall.

We met tons of these students who were enthusiastic about their projects and the future of solar and other alternative energies. Their positivity was contagious! Go down there and check it out before it's too late!

No comments:

Post a Comment