MONDAY 16 JULY, 2012 |
What Is A 'Plug And Play' Grid Tie Solar Inverter?
Plug-in grid connect solar inverters have begun appearing in Australia - so what
are they, how do they work and should you use one?
A solar inverter is a box of electronics that takes the electricity generated by
an array of solar panels and converts it from Direct Current (DC) to Alternating
Current (AC); suitable for use by home appliances and for export to the mains
A traditional solar
can handle the output of multiple solar modules and is usually
installed close to the meter box. Microinverters, a more recent development, are
much smaller units that work with single panels and are located on the back of
the module itself; creating what is often referred to as an AC
The most common type of solar inverter used in home power installations needs to
be installed by a qualified person as they are hard-wired into to the meter
The new "plug and play" inverters are very different - these are a
portable device that allow you to connect solar panels or small wind turbine to
the inverter and then plug the inverter directly into a standard power socket in
a home; making the power generated available to appliances. While not having as
much capacity as a standard residential solar inverter, multiple units can be
It sounds like a great idea, but consumers considering purchasing a plug and
play grid tied inverter may need to be cautious.
In a discussion concerning these units on Energy
, one of the points mentioned is while plug and play inverters
may be listed by the Clean Energy Council (CEC) and approved for Renewable
(RECs), their certification under an important safety
standard still appears to questionable.
The standard, AS-4777, deals with grid connection of energy systems via
inverters. In order to be listed by the CEC, inverters "must be tested against AS 4777.2 and 3 - 2005 (or equivalent) and AS3100 (or equivalent) by an appropriate testing laboratory."
However, in AS 4777.1 (Installation Requirements, Clause 5.3.1), it apparently
states "the inverter shall be connected by fixed wiring to a dedicated circuit on a
switchboard". This would seem to prevent the use of any plug-in type device
if AS-4777 is strictly observed.
Another important issue involves electricity distributors. Before any
electricity generator can be connected to a network (which includes your house
when solar panels are capable of exporting electricity to the grid), permission
from the distributor must be gained. This permission doesn't consist of a quick
call to the company and a verbal "yep, you're good to go" - there is
Additionally, safety of these units has also been raised. While a plug-in
inverter may have anti-islanding features that prevent the unit from delivering
power in a blackout, electricity may still be delivered for up to 2 seconds. If
the plug were pulled from the outlet, it could still potentially deliver a nasty
Finally, consumers considering installing a plug and play grid connect inverter
should check with their insurance company to ensure using such a device doesn't
impact on home insurance policy coverage, particularly as a DIY project.
While a great idea in theory, it's these potential issues that have led some to
refer to plug in grid tie inverters as "plug and pray".
All Solar Inverters Are Equal
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