Electrical guru's help please!!

[will_raymo2000]

Got everything ready for my brewday today on my new 10gallon HERMs set up. Water treated and ready to heat to strike temp...

Then boom.. boiler RCD goes click. I fear the worst but see that its only a blown fuse, replace it, and click. Blown another fuse. It's a quality element, the pigtail one from the heating element company. I measured the resistance - 19.2 ohms. This is what it should be reading going by the formula V^2/R -- (240*240)/19.2=3,000 watts.

I have installed it as it should be, as far as I can see there are no problems and I cant understand it! I have a 13mm ring crimp round the mounting of the element for the earth connection and then 2 ring crimp connectors for the power. I assume they arent polarity sensitive??


Can anyone suggest something to look for?! And no, it's not leaking. I sealed it with silicone washers on the element side and used the standard copper washers on the connection side.

Thanks!

 

[theboytony]

try seeing if there is a reading down to earth

 

[EskiBrew]

Sounds like the element has an earth leakage fault - or possibly the wiring - you'd probably need a megga to check for sure. Before assuming that is definitely it though, can you give details about the RCD you are using - it sounds like you are using an RCD close to the boiler. You're not running more than the one element from it are you?

 

[will_raymo2000]

Sounds like the element has an earth leakage fault - or possibly the wiring - you'd probably need a megga to check for sure. Before assuming that is definitely it though, can you give details about the RCD you are using - it sounds like you are using an RCD close to the boiler. You're not running more than the one element from it are you?

The wiring goes - crimp connectors to twin and earth cable, through cable gland to RCD plug from B and Q. Seems a fairly standard unit, 30mA 13amp rating.

The wiring in my brewing room is fairly heavy duty and has its own rcd in the consumer unit which isnt tripping. The boiler was the only thing connected at the time of testing although I have previously run brewed with a boiler with 2 2.4kw elements in the same room no problem.

The element was used yesterday to boil roughly 40litres of water for over 30mins as a test for leaks. No leaks were found so I concluded no problems yet today came to use it and off it went with its list of issues!

 

[Runwell-Steve]

My money is on the Been n screwed RCD being knackered.

I am not an electrical guru though, far from it.

 

[gunner]

Hi there,
just as a matter of interest, we have just finished selfbuilding our new home. Out of approx 30 RCDs (all from a supposed top make) 4 were defective straight out of their boxes. When I asked the electrician about this, he said that was about par for the course, and that he'd had batches with even more defective units than that, so i think I'd try a new RCD first

regards

gunner

 

[Springer]

Been n screwed

:lol:

Yes I have stopped going there, I probably found what I wanted and then my blood pressure rose rapidly when I saw the silly price they are asking. :evil: On line or a proper place for me, hate sheds.
S

 

[EskiBrew]

The wiring in my brewing room is fairly heavy duty and has its own rcd in the consumer unit which isnt tripping. The boiler was the only thing connected at the time of testing although I have previously run brewed with a boiler with 2 2.4kw elements in the same room no problem.

It's actually not good practice to use more than one RCD in a circuit unless one is an S rated (time delayed) device. Details can be found in the 17th edition IEE regs. That however is not causing your problem.

Since you already have an RCD in the consumer unit, then if it is a 30mA standard timed device, there is no need to have another one in the boiler supply. Remove the boiler one and try again. If the main RCD trips then it definitely looks like a real earth fault otherwise it might just be that B&Q RCD playing up. Some things to consider before anything else:
1) Could the B&Q device have some condensation from any steam produced in your previous trial?
2) Could your previous trial have overheated any of the boiler wiring - have you double checked the insulation?

HTH :thumb: