Friday, December 6, 2013

Response to article on Fire Safety and Solar

Article can be found here:

Edgeworth and Sewickley don’t need new code restricting their home owners’ rights to own solar and become Energy Independent…they need education so they clearly understand solar safety which we are happy to provide.

The danger solar poses to firefighters is greatly exaggerated.  Solar is less dangerous than a service supply from a utility carrying only a small fraction of the amps when operating at full capacity and the racking the solar is mounted to is actually an asset to firefighters in adverse weather conditions.

A typical residential solar array consists of 1 to 3 strings of 8 Amps each.  A typical service entry wire that is on every home is carrying 100-200Amps.  Though under the right circumstances 8 amps could be fatal, it pales in comparison to the 100Amps currently present on every home.

The code already dictates that a clearly labeled utility accessible and lockable solar disconnect must be installed within 10 feet and visual site of the service meter to disconnect any solar array.  Once this is triggered there are no longer any Amps present in the solar array.  See UL 1741.  There is no such code for service entry wire carrying far more power.

Even after the AC disconnect is triggered, there is still voltage present when the sun is out which when grounded can make an arc which can be dangerous.  However, without the inverter allowing the current to flow the arc is a DC spark.  Not to say that in very rare circumstances this could cause injury or be fatal, it would be a very rare occurrence.  Our crews wire these panels on sunny days all the time.  We have yet to have an injury on any install in our history of over 140 local systems.  This is not to say we have never had anyone touch both sides of the circuit and cause themselves to be energized on a sunny day.  It has happened but it is such a small amount of current it is little more than an uncomfortable sensation.

Even this voltage potential can be heavily mitigated to eliminated using today’s current technology.  The Falk’s mentioned in this article for example are using an inverter system made by SolarEdge that has a built in safety feature which limits all DC voltage in roof circuits to 1V when the inverter is not engaged.  At the same time it conforms with UL 1741 and stops all Amperage.  This means it is less dangerous than touching a 9V battery to your tongue once the exterior disconnect is triggered.  There are three such technologies readily available, we have installed all of these technologies in or around Sewickley.

As far as roof access safety, the solar also helps in this area.  Western PA has abundant steep roofs.  A steep roof is treacherous under dry conditions and deadly under wet or icy conditions.  We are installing solar in Sewickley this week on a very steep roof.  The work is very difficult until the racking is set and attached to the home.  After this step it is easy to navigate the roof since the racking allows a safe tie off, something to stand on, hold on to and catch if you are slipping.  Firefighters who understand the method of racking can utilize the racks as a safe place to hang on to when cutting into roofs.  Removing panels to allow for shingle access takes only a few seconds and since the panels are wired together, they will not drop on others working on the ground below.  Removing two clips that will pop off with a tap of a fireman’s ax opens an area 6ft by 8ft with two rails crossing the opening, each capable of sustaining the entire weight of a fully clad fireman.  Imagine how beneficial this would be for a fireman on a steep icy roof in the middle of winter.

Solar is not the problem, education is the problem.  Solar is safe and beneficial and we will happily speak to any municipality or firehouse about this, provide educational information, bring panels, clips raking and provide site access to a variety of actual installs to help prepare our firefighters to deal with this safety asset on the roof called solar.  Two of our installers are active volunteer firemen and their safety is our greatest concern.

Joe Morinville:

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