The Fire System Annunciator is displaying Earth Fault to –VE on external wiring (or +VE)
Take a meter set to DC voltage in order to isolate the fault with these following steps:
- There are 5 wires that come from the power supply on the motherboard…. Blue, grey, red, black and green/yellow.
- On a normal panel between earth ground (green/yellow) and black (DC negative) there should be about 1VDC.
- If the voltage is below 0.3VDC the panel will be in –VE fault.
- If the voltage is above 1.5VDC the panel will be in +VE fault.
- In order to find out what loop is faulted, remove the wires one at a time with a meter connected to the terminals in step 2.
Part numbers D10024A, D10024, D9024, D8024