Exploded SSR / Loud Pop / PLEASE HELP

Firewalker11 · May 1, 2016

NoIguanaForZ said:
A GFCI is detecting current "lost" to ground. Generally speaking, this is most salient when the current is being "lost" because the operator has inadvertently placed him/her/themself in series with ground.

So the original statement that a GFCI would remove most of the danger is correct.

(It wouldn't help if you'd grabbed the red and black wires, though).

Perhaps I can piggyback on your post? I was looking at this GFCI issue solely from the ability of the GFCI to work as an heat or amperage breaker due to the load being controlled by a light switch.

I agree 100% that a GFCI is essential in this circuit and all, I just read into it that it would also act as a circuit breaker under overload conditions.

Sorry I didn't clarify and that I came off as a troll. I had no intention of doing so.

Thanks NoIguanaForZ for your insite.

dyqik · May 1, 2016

r8rphan said:
You are fine running any load through a device up to 80% of rated load.. Above that, you are technically violating code...

So a 15A switch is fine up to 12A (basically up to about 1400 watts) and it should last for quite a while...

Same with a receptacle... But be careful how receptacles upstream in the circuit are wired.. If they are through wired instead of pigtailed, then whatever you plug in down stream from them has to flow through the receptacle.. This is what causes kitchen fires, especially if the through wiring is stabbed in.. Stabbed in wiring on switches is also problematic.. I don't do it, I pigtail everything, and then side wire all devices...

So a 5500 watt heater element draws 24.9A, which is 80% of 29.9A... So with a 30A switch you are right up against the limit...

They make motor rated switches by horsepower which look the same and can handle more.. But the thing is, that 5500w is not a continuous load, It rarely runs at that power for extended periods.. The PID controlled relay should be operating at a reduced duty cycle.. and if you are worried about it in manual mode, just run it at something less than 100%.. like 85-90% and then you have plenty of breathing room...

FYI, when sizing wire, calculate the max 'continuous' load and multiply by 1.25... The result of that is how you size your wire according to NEC table 310-16.. Your breaker is sized to the wire.. If no corresponding breaker size exists for your rated wire current, then you are allowed to go up to the next common size...

For instance #6 THHN is rated at 75A.. You can use an 80A breaker on it because 75A breakers do not exist...

I think this bears repeating loudly: As you say in the middle, the 80% derating is for _continuous_ loads only, defined as lasting over 3 hours. So derating doesn't apply to typical brewing operations.

You are fine running 14A through 15A switch and a 5500W element on a 30A switch and circuit in the likely use case here.

doug293cz · May 1, 2016

r8rphan said:
BTW, I really don't know how the PID is wired, and won't until I get one in my hands, but one possible use where a contactor would be handy (and add some sexy), is if what Casey said is true, and the alarm contacts on the PID are nothing more than an isolated switch, then you could use momentary on off push button switches to energize the contactor and the use a holding loop where the alarm contacts were in series with the off push button in the holding loop... Both the alarm contacts, and 'off' push button would need to be normally closed contact though.. and I'm really not sure how the alarm contacts are configured (they need to be of the rated voltage used too).. The 'on' push button would be configured normally open..

Put the contactor in series with the incoming 240v supply circuit and then if the alarm circuit triggers, it shuts power off to 'everything'... Just like the off push button would..

just a thought...

The alarm on the MyPin TD4-SNR is an NO contact, so no-go with your idea.

In any case the alarm function in a mashing/boiling application is kind of worthless. You don't want to set the trip point below boiling (for mash mode), or you will have to reset the trip temp every time you switch between mash and boil mode. And, when would it ever trip if the trip temp was set above boiling?

That said, I do show how to wire an alarm in the schematic I'm about to post. But, I wouldn't bother with it.

Brew on :mug:

Firewalker11 · May 1, 2016

dyqik said:
I think this bears repeating loudly: As you say in the middle, the 80% derating is for _continuous_ loads only, defined as lasting over 3 hours. So derating doesn't apply to typical brewing operations.

You are fine running 14A through 15A switch and a 5500W element on a 30A switch and circuit in the likely use case here.

Does this also include the feeder wiring?

doug293cz · May 1, 2016

Here's my version of the design. It has a couple of extra features compared to OP's original design:

Both "Element Power On" and "Element Firing" indicator lights
A switched outlet for the pump, and an non-switched outlet for whaterver

I show the pump and PID power switches grounded. If there is not an obvious way to attach ground wires (depends on the switches used), then these connections can be omitted. If the controller is in a metal enclosure, then the enclosure also needs to be grounded. I would leave the alarm disconnected, for reasons stated previously. The alarm can be wired to a buzzer (shown), light, or combo lighted buzzer. A switch in series with the alarm indicator can also be convenient to enable/disable the indicator.

Any questions, just ask.

Brew on

doug293cz · May 1, 2016

r8rphan said:
...

So a 5500 watt heater element draws 24.9A, which is 80% of 29.9A... So with a 30A switch you are right up against the limit...

...

5500W @ 240V works out to 5500/240 = 22.9A, and 22.9/30 = 0.764. So, lots of margin here.

Brew on :mug:

Gavin C · May 1, 2016

doug293cz said:
Here's my version of the design. It has a couple of extra features compared to OP's original design:

Both "Element Power On" and "Element Firing" indicator lights

A switched outlet for the pump, and an non-switched outlet for whaterver

I show the pump and PID power switches grounded. If there is not an obvious way to attach ground wires (depends on the switches used), then these connections can be omitted. If the controller is in a metal enclosure, then the enclosure also needs to be grounded. I would leave the alarm disconnected, for reasons stated previously. The alarm can be wired to a buzzer (shown), light, or combo lighted buzzer. A switch in series with the alarm indicator can also be convenient to enable/disable the indicator.

Any questions, just ask.

View attachment 352608

Brew on

Over and above the call of duty on this last post Doug. Fantastic.

When I go electric, just a heads up, I'm going to be picking your brain mercilessly. Not on the horizon just now.

Thanks also the the many other learned and helpful contributors to this thread. A lot of it is greek to me but hopefully one day thanks in part to discussions like this I can reciprocate.

Tangent over. Back in my box

doug293cz · May 1, 2016

brandonring said:
I threw back a few delicious Tree House beers last night and came up with this diagram. It looked better to me last night but here she is in her cluttered glory. Round 3.

I still have the neutrals switched because I currently have easy access to the double pole rocker switches. I'm still kinda in the dark (pun intended) when it comes to the lights. Am I getting closer?

This looks much better than your previous schematics.

The only problem is with your element firing light. It won't work the way you think it will. With the element power switch on, the light will be receiving 120V thru the element, which will cause it to light partially when the SSR is off. It will light at full brightness when the SSR is on. Better to use a 240V lamp wired between the two hots between the switch and elements.

You can either switch both the hots and neutrals, or just the hots. You don't have to use both sets of contacts on the switches. Not switching the neutrals reduces the total number of connections that need to be made (and can fail.) What you are not allowed to do is switch just the neutrals without switching the hots.

I prefer to put the element power switch for the hot line going thru the SSR between the power feed and the SSR, rather than after the SSR. This allows the use of both"Element Power On" and an "Element Firing" indicator lights. Also, cuts off power closer to the feed inside the panel. That said, many designs successfully put one side of the switch after the SSR.

Brew on :mug:

brandonring · May 1, 2016

doug293cz said:
Here's my version of the design. It has a couple of extra features compared to OP's original design:

Both "Element Power On" and "Element Firing" indicator lights

A switched outlet for the pump, and an non-switched outlet for whaterver

I show the pump and PID power switches grounded. If there is not an obvious way to attach ground wires (depends on the switches used), then these connections can be omitted. If the controller is in a metal enclosure, then the enclosure also needs to be grounded. I would leave the alarm disconnected, for reasons stated previously. The alarm can be wired to a buzzer (shown), light, or combo lighted buzzer. A switch in series with the alarm indicator can also be convenient to enable/disable the indicator.

Any questions, just ask.

View attachment 352608

Brew on

Doug you are amazing!

doug293cz · May 1, 2016

brandonring said:
Doug you are amazing!

Thanks, and you're welcome. I do it because I enjoy it, and want to help where I can.

Brew on :mug:

r8rphan · May 1, 2016

doug293cz said:
5500W @ 240V works out to 5500/240 = 22.9A, and 22.9/30 = 0.764. So, lots of margin here.

Brew on

240v is not what is used for calculation.. The acceptable voltage range is 220v -240v... (110v-120v for 115v)..

So calculations are done using the 'ideal' target voltage of 230v.. That is what the generating plant seeks to deliver to your premises... Load on the system (or lack thereof), voltage loss due to long wire runs, etc. can affect the system voltage, both at delivery point, or at point of use... If you put a meter on your service, and watch it throughout the day, especially in summer months when all your neighbor's A/C is running (or your own), you'll see the voltage delivered to your service vary quite a bit....

That's why the code requires calculating voltage loss into your on site wiring... In most counties in Ca, they actually make you show it as part of your green sheet when installing a new service or upgrading an old one.. No more than 3% max voltage drop to any subpanel, 3% to point of use on the branch circuit from the breaker, 5% max total from service to point of use...

I made a typo in the first number (but not the second), as 5500/230 = 23.91304348 and that times 1.25 = 29.89130435... I rounded off, as there's not really much point in carrying it out 8 decimal places... Having installed 'hundreds' of residential services, I'm very familiar with all of this... and it's a royal PITA in general..

But we're splitting hairs here... The duty cycle of a PID controlled heater element will be significantly lower than 100% continuous load, and even in manual mode, you're not going to be running at max for that long before you back it off..

But if you're worried about it, just set it to something less than 100% and wait a couple minutes longer for it to get to boil... I personally, would not worry about it.. The 'worst' that is going to happen is a slightly reduced switch life..

Unless you wire the switch to short both hots together, then the switch life is gonna be 'significantly' shortened.. lol

r8rphan · May 1, 2016

doug293cz said:
Here's my version of the design. It has a couple of extra features compared to OP's original design:

Both "Element Power On" and "Element Firing" indicator lights

A switched outlet for the pump, and an non-switched outlet for whaterver

I show the pump and PID power switches grounded. If there is not an obvious way to attach ground wires (depends on the switches used), then these connections can be omitted. If the controller is in a metal enclosure, then the enclosure also needs to be grounded. I would leave the alarm disconnected, for reasons stated previously. The alarm can be wired to a buzzer (shown), light, or combo lighted buzzer. A switch in series with the alarm indicator can also be convenient to enable/disable the indicator.

Any questions, just ask.

View attachment 352608

Brew on

Thanks for the diagram.. Yours shows the PID connections and what they are, and that will help me greatly in planning until I order mine and have it in my hands...

:mug:

On your fuses, are you using actual fuses or resettable breakers (ie push button breakers)?

doug293cz · May 1, 2016

r8rphan said:
240v is not what is used for calculation.. The acceptable voltage range is 220v -240v... (110v-120v for 115v)..

So calculations are done using the 'ideal' target voltage of 230v.. That is what the generating plant seeks to deliver to your premises... Load on the system (or lack thereof), voltage loss due to long wire runs, etc. can affect the system voltage, both at delivery point, or at point of use...

That's why the code requires calculating voltage loss into your on site wiring... In most counties in Ca, they actually make you show it as part of your green sheet when installing a new service or upgrading an old one..

I rounded off, as there's not really much point in carrying it out 4 decimal places... Having installed 'hundreds' of residential services, I'm very familiar with all of this... and it's a PITA in general..

The question is at what voltage does the element actually deliver it's rated power? At any lower voltage, it will deliver lower power, and draw less current. If the element can deliver rated power at less than the maximum possible line voltage, then power at max possible voltage needs to be determined in order to calculate max possible current draw. A possible complicating factor would be if the element had a negative temperature coefficient of resistance. To my understanding, the elements we use have small positive temp coefficients, so we don't have to worry.

Brew on :mug:

doug293cz · May 1, 2016

r8rphan said:
Thanks for the diagram.. Yours shows the PID connections and what they are, and that will help me greatly in planning until I order mine and have it in my hands...

On your fuses, are you using actual fuses or resettable breakers (ie push button breakers)?

Either could be used. I don't think there is any benefit to using a breaker for the PID fuse. It might be advantageous to use a breaker for the pump outlet, as it is more likely that the pump could overload without an actual permanent fault condition.

Brew on :mug:

caseyw · May 1, 2016

doug293cz said:
The alarm on the MyPin TD4-SNR is an NO contact, so no-go with your idea.

In any case the alarm function in a mashing/boiling application is kind of worthless. You don't want to set the trip point below boiling (for mash mode), or you will have to reset the trip temp every time you switch between mash and boil mode. And, when would it ever trip if the trip temp was set above boiling?

That said, I do show how to wire an alarm in the schematic I'm about to post. But, I wouldn't bother with it.

Brew on

Popping in for one last note, his idea absolutely would work, it doesn't matter if the contacts on the controller are NO. He just needs to use a pilot relay with the coil voltage for the contactor going through the NC contacts of his pilot relay. I drew a mock up a few posts back and attached as a PDF.

doug293cz · May 1, 2016

caseyw said:
Popping in for one last note, his idea absolutely would work, it doesn't matter if the contacts on the controller are NO. He just needs to use a pilot relay with the coil voltage for the contactor going through the NC contacts of his pilot relay. I drew a mock up a few posts back and attached as a PDF.

You can always add additional components to accomplish just about any functionality. My point was that the PID doesn't provide any NC contacts natively.

Brew on :mug:

passedpawn · May 1, 2016

doug293cz said:
The question is at what voltage does the element actually deliver it's rated power? At any lower voltage, it will deliver lower power, and draw less current. If the element can deliver rated power at less than the maximum possible line voltage, then power at max possible voltage needs to be determined in order to calculate max possible current draw. A possible complicating factor would be if the element had a negative temperature coefficient of resistance. To my understanding, the elements we use have small positive temp coefficients, so we don't have to worry.

Brew on

I did measure the current (using a clamp-on ammeter) and voltage across the element once. I'll try to track down that info. From memory, seemed like 235VAC, resulting in lower current. I figured I was getting line losses (I*R) from the line from the breaker box, in the connectors, and through my SSR's. I was pretty happy that I was still getting most of the power at the element though.

Talk about temp coefficients, measure the resistance of an incandescent light bulb and do some math. There's a HUGE temp coefficient there.

doug293cz · May 1, 2016

passedpawn said:
I did measure the current (using a clamp-on ammeter) and voltage across the element once. I'll try to track down that info. From memory, seemed like 235VAC, resulting in lower current. I figured I was getting line losses (I*R) from the line from the breaker box, in the connectors, and through my SSR's. I was pretty happy that I was still getting most of the power at the element though.

Talk about temp coefficients, measure the resistance of an incandescent light bulb and do some math. There's a HUGE temp coefficient there.

In an incandescent bulb, you're talking about ~2000˚ - 3000˚F temperature differential. That's way outside of the range we "should" see in brewing. The temp coefficient is ΔR/ΔT.

Brew on :mug:

passedpawn · May 1, 2016

doug293cz said:
In an incandescent bulb, you're talking about ~2000˚ - 3000˚F temperature differential. That's way outside of the range we "should" see in brewing. The temp coefficient is ΔR/ΔT.

Brew on

Right. With incandescent, it's a 10x change in resistance. Pretty impressive. Brewing element shouldn't exceed 212F. Shouldn't

Depends on how you clean your element.

doug293cz · May 2, 2016

passedpawn said:
Right. With incandescent, it's a 10x change in resistance. Pretty impressive. Brewing element shouldn't exceed 212F. Shouldn't

Some Google searches confirmed that W (light bulb filament) has a positive TCR. So, I assume you mean that if you measure the resistance at room temp, you will predict much higher current at operating temperature than you actually observe.

The pic of the glowing red element is still less than 1500˚F. You want white light you need to be a lot hotter.
Brew on :mug:

dyqik · May 2, 2016

doug293cz said:
The pic of the glowing red element is still less than 1500˚F. You want white light you need to be a lot hotter.
Brew on

Although brewing with white light may put you at risk of skunking your beer.

dyqik · May 2, 2016

Firewalker11 said:
Does this also include the feeder wiring?

This is the NEC code for permanent wiring within the walls of a building running from the breaker to the outlet or permanently wired load. You are good to use the full rated current continuously for up to three hours, but should use a higher rated circuits for permanently wired loads that are designed to run for more than 3 hours continuously.

Wiring, e.g. in a control panel, that can be disconnected with a plug and socket isn't subject to exactly the same rules (which is why you can wire a plug-in lamp with 18g and connect it to a 15A circuit), as the wires aren't permanently attached to the structure, but it makes sense to use the same ratings there to keep things simple.

dyqik · May 2, 2016

r8rphan said:
240v is not what is used for calculation.. The acceptable voltage range is 220v -240v... (110v-120v for 115v)..

So calculations are done using the 'ideal' target voltage of 230v.. That is what the generating plant seeks to deliver to your premises... Load on the system (or lack thereof), voltage loss due to long wire runs, etc. can affect the system voltage, both at delivery point, or at point of use... If you put a meter on your service, and watch it throughout the day, especially in summer months when all your neighbor's A/C is running (or your own), you'll see the voltage delivered to your service vary quite a bit....

The power ratings of heating elements are specified at 240V, not 220V or 230V. For current calculations for the heaters we use in brewing, you need to use 240V, not 230V, to determine the resistance of the element, and realize that the delivered power is likely less at 230V.

There's also a bit of variation within each production run of elements and between production runs.

My kettle element reaches 5450 W at 240V (measured with current/voltage/power meeting I built into my simple SSVR controller). Typically my supply voltage varies between 237V and 242V.

Bobby_M · May 2, 2016

dyqik said:
The power ratings of heating elements are specified at 240V, not 220V or 230V. For current calculations, you need to use 240V, not 230V, to determine the resistance of the element, and realize that the delivered power is likely less at 230V.

Yes. Every element I've had in my hands is marked as power at 240v. Actual power is derived by actual voltage.

passedpawn · May 2, 2016

Here's the measurements I made on my system a few years ago. This is with a Camco 5500W element

passedpawn said:
233.5VAC measured with multimeter.

22.01 measured with clamp-on ammeter.

So that's only 5139 Watts of heat from my element.

Gavin C · May 2, 2016

passedpawn said:
Right. With incandescent, it's a 10x change in resistance. Pretty impressive. Brewing element shouldn't exceed 212F. Shouldn't Depends on how you clean your element.

http://www.youtube.com/watch?v=nKG3UjT0Wz4

Love it!

I've heard you mention this method of cleaning before. How long are you powering it dry there? Few seconds?

Does the element flex as it heats in the video. I didn't know they did that. Great video.

Not sure I'd be brave enough to try this. (It's moot now as I don't use electric but one day I will.)

passedpawn · May 2, 2016

Gavin C said:
Love it!

I've heard you mention this method of cleaning before. How long are you powering it dry there? Few seconds?

Does the element flex as it heats in the video. I didn't know they did that. Great video.

Not sure I'd be brave enough to try this. (It's moot now as I don't use electric but one day I will.)

Just a few seconds after it gets red. That's all it takes. Everything turns to ash. Regarding that slight movement of the element when heated, I guess that's the coefficient of expansion of the materials at play there.

Gavin C · May 2, 2016

passedpawn said:
Just a few seconds after it gets red. That's all it takes. Everything turns to ash. Regarding that slight movement of the element when heated, I guess that's the coefficient of expansion of the materials at play there.

Makes sense.

I clean my grill in a similar lazy manner. Turn all all the burners for 10 minutes or so with the lid down.

Dracarys!

r8rphan · May 2, 2016

dyqik said:
The power ratings of heating elements are specified at 240V, not 220V or 230V. For current calculations for the heaters we use in brewing, you need to use 240V, not 230V, to determine the resistance of the element, and realize that the delivered power is likely less at 230V.

There's also a bit of variation within each production run of elements and between production runs.

My kettle element reaches 5450 W at 240V (measured with current/voltage/power meeting I built into my simple SSVR controller). Typically my supply voltage varies between 237V and 242V.

Well, if you want to get technical about the calculations of 'appliances' (I was speaking to the code), then you are supposed to have it UL tested, whereby the UL inspector will make the call if it's safe or not, and the appropriate UL label applied..

But now we're 'really' splitting hairs, as no one in their right mind would spend the 25k-75k it costs to get a UL listing these days on such a thing (unless they were planning on manufacturing them).. lol

The bottom line is, the 30A DPDT switch is perfectly fine to use for this application..

Calculating at 240v (which is not standard practice for things that the NEC applies to), makes this even 'more' true... not less...

The discussions here are using the NEC as a guide as to what is considered safe... They are generally 'way' conservative in what is safe.. I know the utility does not have to restrict itself near as much.. They often use much smaller wire coming to the service than we are required to use for the service drop...

My purpose in jumping into this discussion at all was to show that he was not really in danger from the short (as it is a GFI protected system), and that 30A DPDT switch is 'fine' for this purpose...

r8rphan · May 2, 2016

Bobby_M said:
Yes. Every element I've had in my hands is marked as power at 240v. Actual power is derived by actual voltage.

That's the device's rated voltage.. Anything 'above' that is 'beyond' the devices rated voltage and considered improper usage...

If you are experiencing more that 240 volts at point of use (or even at service entrance), I'd contact the utility and have them fix it... (like wise if below 220v)

Exploded SSR / Loud Pop / PLEASE HELP

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