Close Call Doing A Brew This Morning

[browndog]

Hi Brewers,
I was doing a brew this morning on my single tier 3V system, everything was proceding as normal, the sparge water was just about up to temp, then I go to take the lid off the mash tun and zap. Thinking I'd imagined it, I touched the lid with the back of my hand and sure enough there was electricity running though it. I've go this senor pen that lights up in the presence of electricity so I grabbed that and waved it around and it appeared that every part of the brewery was live. I switched off the HLT and this fixed the problem. Hmmm.. I thought, one of the heating elements in the HLT has shorted. So I unplugged the elements and proceded with the sparge and boil. During the boil I refilled the HLT to cover the elements and plugged them back in and switched one on at a time to isolate the bad one, oddly enough, neither got the system live again and even with both runnng I could not replicate the problem. I opened the switch box expecting to see a bare wire maybe or some such and all proved to be OK. Very perplexing, I ran a multimeter over the element contacts while they were still in the HLT expecting to see a short to earth, but got nothing. I then removed them and cleaned them up looking for pinholes but could not find any. I'm getting a sparky mate to come over and check the whole thing out and maybe install a ELCB while he is at it. Any thoughts?


cheers

Browndog

ironically enough the beer was a Green Flash IPA clone, one flash and your ash!

 

[dent]

This is why your metal components with elements inside should be earthed, so even if the element or wiring shorts, it will trip the breaker rather than just livening up your whole rig.

 

[browndog]

This is why your metal components with elements inside should be earthed, so even if the element or wiring shorts, it will trip the breaker rather than just livening up your whole rig.

Yes, I assumed it was earthed as the elements have a 3 pin computer-type plug that has an earth pin that I wired to earth in the swtich box.

 

[roller997]

BrownDog,
What type of elements did you have?
There were some immersible elements which eventually had the water leak through the plastic housing into the guts of the element.
I am looking at using quite a few elements so I want to make sure that I don't liven up the pots or brew structure with live power.
Keep us updated on what your sparky mate finds.

Regards

Roller

 

[browndog]

BrownDog,
What type of elements did you have?
There were some immersible elements which eventually had the water leak through the plastic housing into the guts of the element.
I am looking at using quite a few elements so I want to make sure that I don't liven up the pots or brew structure with live power.
Keep us updated on what your sparky mate finds.

Regards

Roller

They are those 6" dia. 1000W elements the LHBS sell for "water purifiers" There is no plastic parts in the inside of the HLT wall with these things.

 

[matho]

Mate get your multimeter on ohms and see if the HLT is earthed by putting one probe on the metal of the hlt and the other probe on the earth wiring in your system it should be a dead short, if not then you will have to earth the pot.
I know that hot water systems can have insulation resistances as low as 100k ohms to earth and that is why they were not wired into an elcb because the can trip them.

 

[Greg Lawrence]

Was it a small tingle (flat 9v battery on the tongue) or a huge belt?
If it was a small tingle, it sounds like a moisture problem. Electricity tracking to earth through water/moisture. Not enough to blow a fuse, but gives you a bit of a fright. An RDC would trip in this condition.
If it was a huge belt, I would assume that the whole system is live, therefore you need to look at your earthing because you should have blown a fuse.

Greg

 

[browndog]

Was it a small tingle (flat 9v battery on the tongue) or a huge belt?
If it was a small tingle, it sounds like a moisture problem. Electricity tracking to earth through water/moisture. Not enough to blow a fuse, but gives you a bit of a fright. An RDC would trip in this condition.
If it was a huge belt, I would assume that the whole system is live, therefore you need to look at your earthing because you should have blown a fuse.

Greg

It wasn't a full belt, but it was a bit more than a tingle, I would have thought the RCD in the house switchboard would have tripped, is it possible that the silicon sealant I used to seal the elements in with insulated the HLT from the earth in the element?


-Browndog

 

[Greg Lawrence]

It wasn't a full belt, but it was a bit more than a tingle, I would have thought the RCD in the house switchboard would have tripped, is it possible that the silicon sealant I used to seal the elements in with insulated the HLT from the earth in the element?


-Browndog

Sounds a bit strange, I would have thought that the RCD would have tripped.
A simple explanation of how an RCD works is the current supplied through the phase should equal the return current on the neutral. If the current on the neutral is lower than on the phase, there must be some earth leakage (this is why they are also called "Earth Leakage Circuit Breakers or ELCBs). The amount of allowable earth leakage is the rated trip current of the device.
Maybe you have a faulty RCD too.

 

[bradsbrew]

I was told by the Energex guy that came to my place after I recieved a zap (bloody dog chewed lead and exposed wires where I grabbed it) that the earth leakage didnt trip because I was the earth. I now pass this info onto all my apprentices in training. DO NOT RELY ON SAFETY SWICHES

Cheers

 

[dent]

Yes, I assumed it was earthed as the elements have a 3 pin computer-type plug that has an earth pin that I wired to earth in the swtich box.

Cool - it would be also good to earth the HLT container itself if possible.

Typical RCDs require 30mA difference between active and neutral current before they will trip - this is actually quite a lot if that is running through you. 10mA is generally quoted as 'painful'. A tingle will not be more than 30mA so your RCDs might actually be working correctly. You can buy from an electrical wholesaler a very basic RCD tester with a plug on one end for less than $30 if you want to make sure.

If everything is earthed correctly then if there is any leakage it will generally trip the RCD right away if it is significant.

 

[stillscottish]

Was the mains plug into your "water purifier" element the correct way round?

I use one of those for purifying water. Part of the moulding disintegrated and the mains connector can now be plugged in correct way or upside down. I used it recently and plugged it in without really looking. With it upside down, the earth isn't connected. Result, a healthy tingle when I touched the metalwork.

I always pay attention now.

 

[browndog]

Was the mains plug into your "water purifier" element the correct way round?

I use one of those for purifying water. Part of the moulding disintegrated and the mains connector can now be plugged in correct way or upside down. I used it recently and plugged it in without really looking. With it upside down, the earth isn't connected. Result, a healthy tingle when I touched the metalwork.

I always pay attention now.

Yep, definitely in the right way around mate, when I originally fitted the elements, I had silicon on the inside and outside, I'm thinking the silicon on the outside may have prevented the element earth from earthing the HLT. Just don't know why it became a problem after 3 yrs.

 

[michael_aussie]

Hi Brewers,
I was doing a brew this morning on my single tier 3V system, everything was proceding as normal, the sparge water was just about up to temp, then I go to take the lid off the mash tun and zap. Thinking I'd imagined it, I touched the lid with the back of my hand and sure enough there was electricity running though it. I've go this senor pen that lights up in the presence of electricity so I grabbed that and waved it around and it appeared that every part of the brewery was live. I switched off the HLT and this fixed the problem. Hmmm.. I thought, one of the heating elements in the HLT has shorted. So I unplugged the elements and proceded with the sparge and boil. During the boil I refilled the HLT to cover the elements and plugged them back in and switched one on at a time to isolate the bad one, oddly enough, neither got the system live again and even with both runnng I could not replicate the problem. I opened the switch box expecting to see a bare wire maybe or some such and all proved to be OK. Very perplexing, I ran a multimeter over the element contacts while they were still in the HLT expecting to see a short to earth, but got nothing. I then removed them and cleaned them up looking for pinholes but could not find any. I'm getting a sparky mate to come over and check the whole thing out and maybe install a ELCB while he is at it. Any thoughts?
cheers

Browndog

ironically enough the beer was a Green Flash IPA clone, one flash and your ash!

You are bloody lucky.
Yes, either get an RCD (earth leakage) switch fitted to your switch board, or go and buy a power board with inbuilt RDC.
The cost is so cheap.
Your life is worth it.

When looking for earthing faults, a simple multi-meter will not necessarily pick up a fault, especially an intermittent fault.

For more definitive earth fault testing you need to use a special meter called a Megger Meter. These instruments apply a high voltage (typically 1000V) and measure the current that flows when 1000V is applied. A faulty component can appear to have a very high resistance when tested with a simple multi-meter, but this resistance can break down under load and hence pass current (and therefore potentially kill).

Your sparky mate will have one, or know where to borrow one.

Oh yeah .. did I mention, get an RCD (fixed or portable) in your circuit.

 

[browndog]

You are bloody lucky.
Yes, either get an RCD (earth leakage) switch fitted to your switch board, or go and buy a power board with inbuilt RDC.
The cost is so cheap.
Your life is worth it.

When looking for earthing faults, a simple multi-meter will not necessarily pick up a fault, especially an intermittent fault.

For more definitive earth fault testing you need to use a special meter called a Megger Meter. These instruments apply a high voltage (typically 1000V) and measure the current that flows when 1000V is applied. A faulty component can appear to have a very high resistance when tested with a simple multi-meter, but this resistance can break down under load and hence pass current (and therefore potentially kill).

Your sparky mate will have one, or know where to borrow one.

Oh yeah .. did I mention, get an RCD (fixed or portable) in your circuit.

Thanks Michael,

There is a RCD in the house switchboard, so I'm surprised that didn't trip, hopefully it is not faulty. I thought I' go to bunnings and pick up a lead with a built in RCD and wire that in place of the lead that supplies power to the brewery and also connect an earth lead from the HLT to the common earth in the HLT swtich box (after checking that the earth in the HLT switchbox is kosher) come to think of it I had the lead from the brewery plugged into a timer and then an extension cord from the timer into a power point. Possibly the problem may have been there somewhere.


cheers

Browndog

 

[michael_aussie]

Sounds a bit strange, I would have thought that the RCD would have tripped.
A simple explanation of how an RCD works is the current supplied through the phase should equal the return current on the neutral. If the current on the neutral is lower than on the phase, there must be some earth leakage (this is why they are also called "Earth Leakage Circuit Breakers or ELCBs). The amount of allowable earth leakage is the rated trip current of the device.
Maybe you have a faulty RCD too.

Gregors description of how a "modern" RDC works is correct.

From memory, the modern RCD switches are more "reliable" than the very early ones... something about the early ones measured earth current, where as the modern ones measure the difference in current between the active and neutral ..... but I could be talking crap.

other possibilities... what you felt was less than 30mA so the RCD is working but didn't come into play.

Maybe the circuit you are using isn't actually protected.
I used to live in a house that had a plug in air conditioner, and its circuit wasn't protected .. the rest of the house was.
Ovens usually aren't protected.
Older houses with RCDs don't have their lighting circuits protected, to some dodgy home handy men who tap into lighting circuits for power have put themselves and their families at risk.
I think fridges and freezers used to be exempt.

Thanks Michael,

There is a RCD in the house switchboard, so I'm surprised that didn't trip, hopefully it is not faulty. I thought I' go to bunnings and pick up a lead with a built in RCD and wire that in place of the lead that supplies power to the brewery and also connect an earth lead from the HLT to the common earth in the HLT swtich box (after checking that the earth in the HLT switchbox is kosher) come to think of it I had the lead from the brewery plugged into a timer and then an extension cord from the timer into a power point. Possibly the problem may have been there somewhere.
cheers
Browndog

Even if your circuit does have an RCD, using an extension lead with an RCD cannot hurt. .. it's like a second level of insurance.

 

[matr]

It's probably the lightning coming from your fermenters due to the excessive yeast caused static electricity.

 

[browndog]

So my Sparkie mate came over today to check out the brewery, prior to his arrival I had removed and cleaned the elements, earthed the kettle and installed an RCD. He started by checking the earth on the elements and then checked them with a megger and pronounced them in top shape, he had a good look at the control box and tested the pump and all was good, he got me to earth the control box door as he said relying on the hinge was not good enough. He tested he powerpoint I had the brewers plugged into and went out and tested the house fuse box earth and tested the RCD in the fuse box and found everything OK. Then he got me to fill the HLT and power up the elements and he did some more testing. In the end he could not pinpoint the cause of the leak but stated with all the extra earthing and the RCD I shoult not have to worry about being shocked any more. We had had some really heavy rain that morning and I reckon it must have been the cause of the leak, my brewery is under an awning and while not exposed to rain, moisture could have been a factor.

cheers


Browndog