car deck and volt meter setup trigger

he just puts the 8 infront when he is out of stock, so if it says ground can be the same, its stating the positive can be the same to then? would load current just tell me how much it will draw, not that it would effect wiring correct? also, does this need a fuse? or should I just wire the thing right into it?Viper 5902 - Ordered

Kicker Dual CVX 15's - Installed

Kicker ZX 1500.1 Amp - Installed

The chip that does the voltage sensing must be supplied independently (isolated) from the voltage it is sensing - it cannot be have any "reference" between the two voltages. Hence it needs to be isolated - aka galvanically isolated - meaning that current cannot from one to the other. If this unit can share GNDs (which is the most common implementation), then is follows that it can share +ve too. (It doesn't have to, but it doesn't make sense to do it other than by full isolation. Then again what I consider sensible isn't always obvious to or reflected by others!) But I suggest asking: - is the (12V) supply independent of its sensing circuit - ie, you can connect the sensing wires to the 12V supply wires/terminals? - what is its max current consumption - eg, for a display of 18.88? - what fuse is recommended for its +12V supply? Normally these are not fused because there is not much to protect - if a fault occurs, then it's dead. You would just ensure the power distribution itself is protected (ie, a fuse to protect the wire that supplies +12V to it; normally the vehicle's gauge/meter circuit is used (typically 5-10A fusing)). The sense inputs need no fusing. But if it is desired, it is better using in-line resistors (ie, 1k to 1M Ohm, 1/4 - 1/2W ratings as explained earlier).