In addition: some coils are rated for momentary use (such as a car horn) while others are rated for continuous use (such as home lighting systems like PIR porch lights or occupancy switches. Use of a momentary coil in a continuous application will lead to excessive heating.

 

Welcome to AAC.

Most relays offer what is called galvanic isolation. That is, they provide a way to separate two different power systems for whatever reason one might have. Often, it is to protect a low voltage system from a high voltage one—but any reason you might want power from one power domain to switch power of another domain without connecting the two, relays are a common isolation device.

The exact level of isolation will depend on the design of the relay, but for all commonly encountered voltages relays are pretty much completely isolating. This is because the contacts that switch whatever you want to control are operated by an electromagnet, and the coil of the magnet is all the controlling system sees.

 

Sorry, I don't think I've explained myself very well. I'm thinking to reduce the number of times I have to dig up the path when the cable moves to the other side I'll just have 2 cables/circuits each running down one side of the path, both switched by a single pir at the garage or house end. Hope this makes sense!?

The diagram in post #2, three 2-wire cables, then parallel and make common as needed to achieve the ckt as shown.
This way you don't need zig-zag wire side to side of the pathway, you just run a cable per side.

If you need a relay, use a SSR.

 

Hi,
Do you live near an airport?
Good luck..............

 

Hi folks, I'm new to this site and to electronics generally. I'm looking for advice/validation. I want to install low level embedded path lights (walkover type) on a winding path from a garage to a house approximately 50m away. Id prefer 12v as digging the trenches for mains cable will be exceptionally difficult due to tree roots, etc. I'd like led lights staggered on both sides of the path, not worked out how many yet but quite a lot! I'd like the lights switched by pir switches at the house end and at the garage end - wired together. To avoid digging up the existing path too much I'm thinking I'll have 2 circuits, 1 on each side of the path. I assume I'll need 2 transformers for this ( located inside the garage). Can i use the 2 pir sensors to switch both circuits? Does this all make sense? Anything else I should be aware of or should I do it completely differently!? Many thanks!

How much ampere is the 1 meter of that led strip you plan to use?