House Electricals





Related Pages:

GI System Main Page
Solar Hot Water System

Electrical Wiring Diagram of the house


Meter Box Photos and Layouts
(Red numbered items correspond to the numbered items in the diagram above and description below).

Inveter meter box Normal meter box

SEA Grid Interactive Inverter (2)


3 Fuses to PV panels (Only 2 used).

Solar Input


4 Protection Relays in a row



1 min


Switch (8)



Normal Supply Main Switch

Hot Water Timer Control (7)

Meter (4)




Digital Meter -
Domestic #1 and
Off-Peak (5)

Domestic #2

Component Description

  1. Solar PV Panels: There are eighteen BP 75 Watt Photovoltaic (PV) panels in the system, making a nominal peak generating capacity of 1350 Watts. The panel configuration is now 2 parallel connected sets each containing 9 series connected panels. (See the System Diary for details of changes made to the panel configuration).
    'Array1' consists of the 9 panels mounted on the house roof, and 'Array2' is the other set of 9 panels mounted on adjustable frames sitting on the carport roof. See the Grid Interactive Photovoltaic System page for more details
  2. Grid-Interactive Inverter: See Grid Interactive Photovoltaic System page for basic details. The recorded total power generated for the day measured by the inverter is usually about 0.1 or 0.2 kWh higher than that recorded by the SunPower Meter (Number 4). This can be put down to (a) losses in the inverter, (b) the inverter draws some power, and (c) the protection devices (Number 3) draw some power.
  3. Protective Devices: These are protection devices installed by our local electricity provider, Integral Energy. The 4 relays detect Under & Over Frequency, and Under & Over Voltage on the incoming power. If any of these conditions occour, then the appropriate relay will open its contacts, thereby removing power from the 1 min Timer, which in turn removes power from the 'Control' line of the Contactor. This cuts power going to/from the inverter. After the condition that caused the relay to open its contacts has returned to normal, power will be re-applied to the 1 min Timer. Once the power has been stable for 1 minute, the timer will close its switch and provide power to the 'Control' line on the Contactor, which in turn allows the Inverter to be connected back into the network.
  4. SunPower Meter: The SunPower meter records how much usable electricity the PV system has produced after taking into account the losses mentioned in (2).
  5. Digital Meter: Nilsen EMS2600
    The Digitial Meter performs several tasks: Functional Diagram of Digital Meter
    • It displays both Domestic & Off Peak electricity consumption in kWh.
    • It contains a ripple receiver, which receives signals from the electricity supplier that switches on or off power to the Off Peak circuit. (Hot Water booster). I'm on the Off Peak 2 schedule.
    • It also displays reactive power, so overall power factor can be calculated.

    Resolution is to 1 kWh, unlike analogue meters which can normally be read to a resolution of 0.1 kWh.

  6. Solar Hot Water System: See Solar Hot Water page for basic details. The booster will only come on when ALL the following criteria are met: (a) The Off peak circuit in the digital Meter (Number 5) is allowing power through, (b) The main hot water switch is 'On', (c) The Hot Water Time Control (number 7) is in an 'on' period or its manual overide is 'on', and (d) The water temperature in the hot water tank has fallen below about 50C.
  7. Hot Water Time Control: See Solar Hot Water page for details.
  8. RCD Safety Switch: This is a protection device which reduces the risk of electrocusion which may occour either through direct contact with live mains or via faulty appliances. Only those circuits that pass through the device are protected. Installation is mandatory in all new houses, and sensible in others.
  9. Normal 240V Electric Circuits: These are the circuits going to all 240V power points, lights etc on the property.

Last Modified : 20/05/04