Evolution of the E-Panel

box included a 60 or 120 amp charge controller as well as DC over current protection and
disconnects.
The inverter breaker was an option, but a 500 amp shunt was standard. These boxes did not
incorporate any AC circuitry. The Heliotrope units were ETL listed and a good value. Sam
Dawson (owner of Heliotrope) was forced to close the doors of Heliotrope after a fire ravaged
the factory, but I hear he is still involved in solar swimming pool equipment.
Trace DC250
The original concept for the DC250 was to use a fused pull out
similar to Ananda until John Wiles steered me to the Heinemann
GJ1 Series breaker. A breaker made a lot more sense because
those pull outs were often difficult to actually pull out. The UL
specs have guidelines to follow for minimum bending room and
I cut it down to the bare minimum. Allowing for more wiring
room would have made the boxes larger and more expensive. It
was a couple of years later that I actually wired up a dual SW
power panel with 4/0 cable. That experience was a real eye
opener for me. The DC250 was a bare bones box built for DC
only. There was one DC load breaker for a DC refrigerator or
power shed light. Later on requests came in for more breaker
slots, so I added three more DC breaker positions. I still did not
fully understand the significance of disconnects for PV
controllers, but the additional breaker slots seemed to satisfy this
requirement. It seemed odd to have breakers protruding out the
sides, but that was the only option available at the time. In ten years there have been no
problems with this arrangement that I am aware of. The DC250 also has an optional tin plated
machined block of aluminum for connection of negative conductors. It also had a 500 amp shunt
as an option. Since Trace was an inverter company, we made the inverter breaker standard and
the charge controller with its breakers optional. This was just the opposite of Heliotrope. The
Trace box originally sold for $295. It may have been basic, but it was priced right. I still believe
the success of the DC250 had a lot to do with the demise of Ananda and Heliotrope. It is
interesting to note that the same DC250 is still sold today by Xantrex.
Trace Power Panel
I had seen only a couple of real installations
by the mid 1990’s. Remember, I’m located
just North of Seattle. The sun doesn’t seem to
work up here very often. There was one
particularly nice installation on a mountain top
in Ukiah CA that Doug Pratt was kind enough
to show me. I was amazed at how well all the
different boxes had been connected together
using conduit and gutters. It was also obvious
to me at this site that every single installation
in the industry was a custom one-off design. A