Simple 120/220v BK

[gnarles]

So i wanted to make a very simple plug in boil kettle.

I am not an electrician by any stretch of the imagination but my idea is to wiring a 220volt 5500 watt heating element into my kettle and have each hot leg on its own switch. I would have them both on to bring the wort up to a boil and then once a boil is reached kill one leg and just run 120v to maintain the boil.

I normally do 5 or 10 gallon batches. will this work?

 

[trimixdiver1]

In short no. Once you open one of the 120v legs, it becomes an open circuit and no voltage will pass.

What you could do is use two elements, or better yet use a temperature controller and SSR to throttle the element so your not pushing the full 5500 watts all the time.

 

[gnarles]

So either run two separate elements each on their own 120 and switch or use a PID controller basically?

 

[Malticulous]

It could work but you don't switch off one leg you switch it to neutral. Will it even keep a boil?

 

[mikescooling]

I would not do that. There's nothing better to use than the current 240v power supply. A PID with manual function will control your power usage.

 

[trimixdiver1]

It could work but you don't switch off one leg you switch it to neutral. Will it even keep a boil?

Good luck not tripping the gfci

 

[Brumateur]

Good luck not tripping the gfci

GFCI will not trip since in/out balance will not be broken.

 

[Malticulous]

A GFCI only trips if there is current on the ground. A 30A/250v SPDT switch would do the job. If the switch stops on center you could even have an off position (don't forget the other leg on the element is still live but the circuit is broke.). It's not much different than a 3-way light switch.

 

[wilserbrewer]

So i wanted to make a very simple plug in boil kettle.



?

This can be done by simply using a large enough kettle, and sizing the element to the kettle and batch size to produce a reasonable boil at 100% element power
Varying batch size is not ideal with a simple e kettle.

IME, 4000'watts will work pretty well for 10'on batches, and 3000 w for 5 gallon batches.


Wilserbrewer
Http://biabbags.webs.com/

 

[trimixdiver1]

GFCI will not trip since in/out balance will not be broken.

If you switch the neutral, then yes it will trip. A GFI monitors the Hot and Neutral lines, not ground.

 

[Minbari]

If you switch the neutral, then yes it will trip. A GFI monitors the Hot and Neutral lines, not ground.

that is my understanding of it too. it makes sure that the incoming current (hot side) is within 5mA of the outgoing current(neutral side). if there is an imbalance, then it trips.

I assume with a 240volt GFCI, that it works the same, just monitors the two hot legs instead. So if you switch a leg to nuetral, then all the current will be sourced by one of the hot legs and returned by the neutral. The 240 volt GCFI will see this as an imbalance and trip.

 

[trimixdiver1]

A GFCI only trips if there is current on the ground. A 30A/250v SPDT switch would do the job. If the switch stops on center you could even have an off position (don't forget the other leg on the element is still live but the circuit is broke.). It's not much different than a 3-way light switch.

WRONG

A GFCI trips on an imbalance of current on the Hot and Neutral lines. Ground isnt even needed when using a GFCI

NEC 406.3

 

[trimixdiver1]

that is my understanding of it too. it makes sure that the incoming current (hot side) is within 5mA of the outgoing current(neutral side). if there is an imbalance, then it trips.

I assume with a 240volt GFCI, that it works the same, just monitors the two hot legs instead. So if you switch a leg to nuetral, then all the current will be sourced by one of the hot legs and returned by the neutral. The 240 volt GCFI will see this as an imbalance and trip.

A 240v breaker still monitors the neutral (you loop the neutral through the breaker then to the neutral buss bar) It monitors both Hot lines against the Neutral for imbalance.

 

[Minbari]

A 240v breaker still monitors the neutral (you loop the neutral through the breaker then to the neutral buss bar) It monitors both Hot lines against the Neutral for imbalance.

ah, ok. never have wired a 240 volt GFCI, so I was doing a bit of guess work. thanks for the info.

the principal is the same though, right? switching the output from 240 volt to 120 volt would cause an imbalance on the neutral and trip it.

 

[trimixdiver1]

ah, ok. never have wired a 240 volt GFCI, so I was doing a bit of guess work. thanks for the info.

the principal is the same though, right? switching the output from 240 volt to 120 volt would cause an imbalance on the neutral and trip it.

It should yes. Some GFCI are more tolerant then the next, but "single phasing" a 240v load will trip it more than likely.

 

[jeffmeh]

My understanding with a properly wired, H1-H2-N GFCI, with H1 used for deriving the 120v circuit, is that the load must balance across all three. On at 240v, H1 must balance H2, as N is at 0. On at 120v, H1 and N must balance, as H2 is at 0. On at both 120v and 240v, H1 must balance H2 + N. Off, everything is at 0. So I would expect it to not trip the GFCI as long as you switched through off when switching between 120v and 240v, which you should be doing anyway as you would not want both H2 and N live at the element at the same time. That said, I have never tried it.

 

[ajdelange]

The goal of a GFCI is to insure that all current going out on either of the phases returns either through the other phase or the neutral. Thus it sums the currents in the two phases and the neutral. If the sum isn't 0 (i.e. there is leakage through earth or any other path) then it trips.

 

[wilserbrewer]

While this is a very informative discussion of GFI's, 120V and 240V, the simple fact remains that a 5500w element at 120V is not enough wattage to boil more than a gallon or two in a small pot, less or even maybe zero in a large kettle. 5500/4 is only 1375 watts, next to nothing and NOT enough!

This can be done by simply using a large enough kettle, and sizing the element to the kettle and batch size to produce a reasonable boil at 100% element power
Varying batch size is not ideal with a simple e kettle.

IME, 4000 watts will work pretty well for 10 gallon batches, and 3000w for 5 gallon batches.

Or you can run a large 5500w with a simple PWM controller, or a PID and SSR.

 

[Malticulous]

WRONG

A GFCI trips on an imbalance of current on the Hot and Neutral lines. Ground isnt even needed when using a GFCI

NEC 406.3

Yes, for it to trip there must be current flowing to a ground somehow, hence a ground fault.

I can boil a five gallon batch fairly well with one of my 2350w burners on my electric stove top. Your element has to be more efficient than that. Maybe not a 1000 watt more. A heat stick could make the difference.