Grounding question

[Annie C]

S&B power from the mains. Two hot lines and one divided between them for a neutral. But it is not a neutral until connected to good old mother earth. Then there is a fourth wire a good old mother earth connection at the power plant and transformers through the grid. The codes restrict the S&B to one cross connection of the neutral and the earth ground. It can only be at the power entry point to the S&B. It cannot be at any sub-panel.
My point is AC from the grid has a connection to the real mother earth, called ground. Obvious reason, I guess.
Some how we started calling vehicle chassis, & negative, ground. But Dc current in a vehicle does not have any reference to mother earth. If we connect our negative battery to the vehicle chassis, the chassis becomes the reference to negative through out the vehicle. Please note I do not recommend using the chassis negative return for any but low ampere, non-critical circuits. My inverter, charging devices, communication devices, refrigerator, and safety devices are all wired with two wires. Positive and negative from the battery, through buss bars. All negative buss bars are also connected to the vehicle chassis. The English with their positive chassis connections called theirs earth. Just more confusion.

There that was exactly why I started reading this. ALL Neg buss bars are ALSO connected back to chassis in addition to having Neg back to the neg side of the house battery. Am I correct?

reason I was reading is I saw a Victron system having Neg on both chassis and neg buss. I am adding the Renogy DCDC/MPPT 50. There is a common neg and > neg buss as well as a neg from the starter battery to neg buss. Am I thinking about this correctly?

 

[Supervstech]

I was going to add to this that there is a potential benefit in having a ground connection to the chassis of the PV panels, in case they’re hit by lightning, but then I realised that unless you ground them with sufficiently thick wire to carry a lightning bolt to ground, you may find your ground wire burns out and the lightning finds a route through your system wiring to the charge controller. Maybe not worth doing then?

Keep in mind lightning grounding isn’t for shunting a strike to ground... direct strikes are massive and nigh uncontrollable... no, the grounding there is to dissipate em waves from nearby strikes, and to dissipate unbalanced fields during storm activity.
ANY ground conductor is better than none, but huge conductors, connected to sharp pointy areas may help balance the clouds and prevent a strike.

 

[JMc]

My experience with lightning is based on a multi-acre property with several buildings. Each building’s electrical service panel was wired per the NEC but in 2002 we added buried cables for computer networking and a security system. There were no lightning arrestors on the buildings because we had numerous tall trees that seemed to do the job fairly well — we never had a direct strike on any structure. BUT — the indirect/induced currents from nearby strikes were a learning experience:

1) A single surge suppressor on a long cable only protects devices nearby, devices on the other end of the cable will be destroyed. Every drop from a network router needs its own suppressor. Each AC outlet needs a suppressor where devices plug in.

2) The best protection in a big electrical storm is to disconnect all power and signals to delicate or expensive equipment. I had a television and two printers destroyed by lightning-induced surge on the attached CAT5 network cable even though all were unplugged from AC power.

3) Wireless or fiber-optic monitoring and control is better than wired networks in situations where frequent lightning occurs.

In a mobile setup with a big storm approaching, I would physically unplug the PV panels and disconnect the rig from AC power and any other network (coax etc.).

 

[Supervstech]

My experience with lightning is based on a multi-acre property with several buildings. Each building’s electrical service panel was wired per the NEC but in 2002 we added buried cables for computer networking and a security system. There were no lightning arrestors on the buildings because we had numerous tall trees that seemed to do the job fairly well — we never had a direct strike on any structure. BUT — the indirect/induced currents from nearby strikes were a learning experience:

1) A single surge suppressor on a long cable only protects devices nearby, devices on the other end of the cable will be destroyed. Every drop from a network router needs its own suppressor. Each AC outlet needs a suppressor where devices plug in.

2) The best protection in a big electrical storm is to disconnect all power and signals to delicate or expensive equipment. I had a television and two printers destroyed by lightning-induced surge on the attached CAT5 network cable even though all were unplugged from AC power.

3) Wireless or fiber-optic monitoring and control is better than wired networks in situations where frequent lightning occurs.

In a mobile setup with a big storm approaching, I would physically unplug the PV panels and disconnect the rig from AC power and any other network (coax etc.).

100% true.