Earthing Electric Elements on your Kegs

[Ciderhead]

To quote JD from another forum


In general, although new kettle elements are safe when used without an earth, this is only true for a very short time. The metal sheath that surrounds the new element is itself earthed. The wort, containing as it does various ions, is sufficiently conductive to provide an earth path to the keg. The problem occurs when the element gets a coating of oxide, crud or limescale. Then the conductivity is lost and safety is compromised. This loss of conductivity is pretty much guaranteed to occur during the very first boil. It is best, therefore, to earth the keg separately from the outset.


You need to use an earth wire bigger than the gauge of the live feed, and in the picture below I went mad and used mains house wiring ensuring there was really good contact between the earth and the wall of the keg.

I read elsewhere you can get away with one earth per keg even if you have 2 elements, I wouldn't risk it.

[JimmyM]

I read elsewhere you can get away with one earth per keg even if you have 2 elements, I wouldn't risk it.

Makes sense.
You just want a route back to earth from the keg. So that if it does become "live", via either of the element or something external, there will be a path straight to earth - hopefully activating earth leakage breaker which will stop the live supply.

By earthing both your elements you are just providing 2 paths - no harm, but not essential.

[Ciderhead]

I read elsewhere you can get away with one earth per keg even if you have 2 elements, I wouldn't risk it.

By earthing both your elements you are just providing 2 paths - no harm, but not essential.

It'd be sods law you'd forget to plug one in or there was a problem with the one you needed, "elf and safety" and all that.

[JimmyM]

Thats a good point actually. Never thought of that.

But ideally it would be earthed off its own earth - like you would with your sink or pipes etc. (I know thats not realistic since you will probably move them around)

But you're right best to earth through both elements.

[JD]

I read elsewhere you can get away with one earth per keg even if you have 2 elements, I wouldn't risk it.

And you would have been right not to like it. Since the earth strap is ultimately connected to the house earth point via the mains cable plugged into the element, it's usefulness applies only when that cable is actually plugged in. Best idea, therefore, is one earth strap per element.

The bit about the earth strap thickness matching or exceeding the thickness of the live wire is best practice. Strictly speaking, what is required is that the earth strap is capable of carrying all the current that the live wire is capable of delivering until the breakers kick out. Most socket circuits are managed by breakers that trip at 20A and most cables are used with 13A fused plugs. Assuming someone replaced the fuse in the plug with a chunk of a six inch nail, the earth strap needs to be able to handle a minimum 20A current. You appear to have used 2.5 mm² solid copper cable. This can handle 27A typically and will suffice in any set up driven by normal household wiring. 

Finally, the bolt and nut connection you've used to connect to the keg, must always be tight to be effective. Loose connections for earth circuits are worse than having no earth because people think they are safe when they are not.

/J|

[Ciderhead]

Thanks JD
You can't see it but I have a double layer of copper wound around the bolt and shes as tight as she will go.
I will also be watching it for corrosion.

[barkar]

Hey i know this post is thread, but i believe my post is relevant . I have a thermopot i butcherred to use for a hlt wired up using a burco element . no leaks / element kicked in and heated water (i didnt touch the pot in case there was a problem) , so all good. I put two earths on it but i want to ensure that its gounded sufficiently . I bought a multimeter ( i havent a clue how to use it ! so correct me if i am wrong)

I set about to test ground which i set at 200 m ohms ()  . i put one pin touching the earth on the plug and the other the base of the element , it jumped around (more to do with my shaky hands) , but settled on 1.4-1.5 . I done the same from the earth on the pot to the kettle element steel backing and again and while it jumped around it came to 1.4 ish . I was told that the resistance should be less than 1 ? Any ideas  dont want :electric: shock

[JD]

Not entirely sure what you're doing but here's what you should do:

1. Get an electrician or someone who knows what they're doing to check.
2. See item 1.

Honestly, all joking aside, this stuff will kill you if you get it wrong. Unless you know exactly what your doing, please stop.

/JD