Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 27 replies
  • Subscribers 32 subscribers
  • Views 2612 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

DC LV Battery Power Supply for Motorhome

TrigPoint
Hi everyone!


I've been asked to install some wiring in a van conversion and I need a bit of advice. The plan is a 110Ah 12V leisure battery, a SELV system and TT earthing (earth electrode from the body of the van.) 


I'm trying to work out the PSCC and PFC so I can choose the overcurrent and fault protection.


So,


a) Is measuring the impedance of the battery and using Uo Cmax / Zs 2R1 (with the measured battery impedance as Zs) acceptable to calculate PSCC


and,


b) Is Uo/Ze (with measured the battery impedance as Ze) acceptable to calculate PFC?


Many thanks in advance for your answers.


Trig


Parents
  • 0

    Nathaniel:

    If the system is just 'safe' voltage, e.g. 12 V, then there's simply no point considering any earthing for safety reasons. In that case the only point in 'earthing' is in the sense of the word commonly used for vehicles, meaning connecting to the metal chassis (not the actual earth) in order to use that as a conductor in the circuit to save on wires. If you're happy to use separate wires for the whole circuit (not the chassis), you'd probably be better to leave the whole 12 V system isolated from the vehicle and earth.


    It's only if there's a source of dangerous voltage involved (e.g. external hookup or internal inverter) that there's any reason to consider connections to  the chassis (other than the functional reason above) or to the actual earth.  In the case that the dangerous voltage is from an internal source and no part of the wiring will leave the vehicle (fixed internal load), there's no point in connections from the vehicle to the actual earth. 

     




    Ah... totally understand. Read up on negative earth. Not necessary to do anything at all. Thanks


    Trig

Reply
  • 0

    Nathaniel:

    If the system is just 'safe' voltage, e.g. 12 V, then there's simply no point considering any earthing for safety reasons. In that case the only point in 'earthing' is in the sense of the word commonly used for vehicles, meaning connecting to the metal chassis (not the actual earth) in order to use that as a conductor in the circuit to save on wires. If you're happy to use separate wires for the whole circuit (not the chassis), you'd probably be better to leave the whole 12 V system isolated from the vehicle and earth.


    It's only if there's a source of dangerous voltage involved (e.g. external hookup or internal inverter) that there's any reason to consider connections to  the chassis (other than the functional reason above) or to the actual earth.  In the case that the dangerous voltage is from an internal source and no part of the wiring will leave the vehicle (fixed internal load), there's no point in connections from the vehicle to the actual earth. 

     




    Ah... totally understand. Read up on negative earth. Not necessary to do anything at all. Thanks


    Trig

Children
No Data

Community Rules & Guidelines