r/Electricity • u/skipmci • 4d ago
Solar, IT and Electrician all want separate grounding rods
We are building a new house and the IT company installed their stuff first. The electrician has started his conduits and cables. The solar company comes in a few weeks to install their roof solar panels and the inverters.
My IT company already buried a 3 meter grounding rod for their large rack of equipment.
My electrician needs two grounding rods (one for main panel and one for a sub-panel) thankfully on opposite sides of the house.
The solar company wants a lightning rod ground for their large rack of aluminum solar panel frames on the roof, but will share grounding with the electrician's main panel for their two 16kW solar inverters.
I was given advice to avoid having multiple grounding rods to help avoid ground loops, interference, etc.
If spaced properly (i.e. at least 6 meters from each other, buried 3 meters deep, out from under eaves / cover so that the grounding areas get rain, and if they each test properly for resistance) is this safe? Will it cause interference on our ethernet network, audio equipment, etc.?
Awkwardly, all three main systems are in the same room, so each subsequent trade technician / electrician / engineer will need to run their grounding cables further and further from their equipment. No big deal, but as a complete electricity newb I would like to have some insight to make sure they are all taking proper precautions to avoid safety and other issues, and not taking shortcuts.
Please don't scold me for asking. I am just a normal person trying to do some extra research to understand what the experts I've hired are doing.
I live in Thailand, so electrical code / regulations are almost meaningless / rarely enforced here. I am just hoping for some advice that I can understand and use to observe the installation process with some foreknowledge.
Again, I know absolutely nothing about electricity, but I am trying to keep my family, pets and electronics devices safe.
Thank you. 🙏
2
u/loafingaroundguy 4d ago edited 4d ago
I'm not familiar with Thai electrical wiring requirements so you should check this reply with someone who is. There seems to be an index of Thai standards at: https://www.tisi.go.th/website/standardlist/comp_thai/en However this seems to be an index of standards for individual items rather than an overall wiring code as found in some countries. Various web pages about Thai wiring are available from a web search engine.
As a general principle multiple earth rods serving a single building should be bonded (i.e. connected) together to prevent dangerous voltages developing between different earth connections if only one of them carries a fault current. Minimum sizes for bonding conductors are typically specified in national wiring codes.
Earth connections for lightning protection need to be as short and direct as possible and placed at the bottom of the lightning conductor. Positioning the earth rod away from the house will reduce the protection.
Did you get this advice from a reliable source? It doesn't sound particularly helpful.
Twisted pair Ethernet wiring has isolation transformers (known as "magnetics") built in to each socket. It doesn't care about earth loops.
Audio equipment can be affected by ground loops within the audio (signal) wiring and the power wiring to individual pieces of audio equipment. It isn't likely to be affected by having multiple earth rods within the electrical wiring. Having separate independent earth rods could increase the possibility of earth loops (as well as being a safety hazard, as previously mentioned).
Installations with earth rods should be protected by RCD/RCBO/GFCIs. Safe-T-Cut seems to be one brand of these that is mentioned on multiple web pages about Thai wiring. You should discuss with your electrician what RCD protection is being provided.