(DG11) DC current in SPX 30 RF ground wire

[Derek - Raymarine - Moderator]

Hi patja

The drain wire,often called the shield is for RF protection and as you state,should only be connected at one end. Generally the drain should not be connected to the -ve volts power wire and so this should be separated.

The Drain is connected to an isolated RF ground plate under the boat, BUT is only used if you have specific EMC issues for example or an SSB which then would require a specific groundplate such as a dynaplate.

The Drain and RF ground connections are provided to meet specific EMC requirements, for test purposes, but in general are not used in the vast majority of installations, since most boats do not experience any find of RF or EMC issues.

In your installation, please separate the Drain and battery -ve connections, disconnect the drain connection on the SPX too.

Regards
Derek