Installation manual

at some distance from a building. Ground-fault protection is not just for residential roofs. The

2008 NEC, requires ground-fault protection for all “grounded DC photovoltaic arrays.”

The NEC lists two exceptions to general GFPD requirements. The first exception is for

ground or pole-mounted systems that are isolated from any buildings and limited to one or

two parallel source circuits. This exception might apply to a remote water pumping system.

The second exception is granted to systems installed at “other than dwelling units”.

Where hydro turbines are remote from dwellings GFPD is not therefore required by the NEC,

but can be installed to reduce fire risk. In grid connected systems inverters have GFPD fitted

as standard, but most off grid MPPT controllers do not. If your hydro turbine is situated in a

very dry bush/forest environments where the fire risk is high, then GFPD should be installed.

There are many such products on the market and some MPPT controllers include GFPD. .

You may not need to earth your PowerSpout bulk head if a GFPD is installed; consult with

your local installer and codes prior to making this decision.

6.4. Avoiding other hazards

6.4.1. Meters to monitor your system

It is important for your safety and for reliable system performance

that you monitor the battery voltage and the hydro production. If

the battery voltage falls too low there may be damage, whereas if it

rises too high there may also be danger of explosion. Check also

that the turbine output is normal so that you can investigate any

problems before the battery becomes excessively discharged.

MPPT controllers or grid tied inverters will display the generation

information for you. A digital volt and amp meter can be purchased

on Ebay from under $20 delivered. It's good practice to install meters in a prominent

position where it will be easy to check the status of the system as part of your routine.

6.4.2. What happens to a hydro turbine when not connected

If a hydro turbine is "open circuit" or disconnected from any load then there will

be no production of current to slow the turbine. A free spinning hydro turbine will

immediately produce dangerous voltages that may also damage your equipment.

Clients new to hydro turbine installation need to be aware that a hydro turbine

designed to connect to a 48 V DC battery, when free spinning can develop up to 200 V DC.

200 VDC is potentially lethal to human contact and to your electronics.

6.4.3. What happens if no controller is installed

Unregulated charging of the battery will ultimately cause it to dry out, overheat

and explode. You must install a controller and check on a regular basis that it is

working. Look at the voltmeter and check the level of the electrolyte.