What happened here? Blown SSR/ Camco 02965 Element/ Wiring?

[M54B25]

I got midway through my most recent brew day on my Kal-clone system and heard a "pop" and everything shut down. Upon investigation, I found that my boil kettle SSR blew apart and tripped the circuit breaker. Since I saw nothing wrong elsewhere and have been using this system successfully for a while with no changes I thought the SSR was maybe bad and swapped it out for a spare. About 5 minutes after firing it back up I heard a similar pop and found a similarly fried SSR.


I checked inside the element connection box and found the reason the SSR was blowing.


I have a spare element (new vs. old comparison):



And I can replace the wire connections but I'm curious if anyone can offer any insight on what actually went wrong here. Obviously there was a short that fried the element and the black wire but I'm not sure why or which one came first? Does anyone see anything that would point to one of these?

Bad element?
Poor connection on ring terminal to element?
Poor connection on ring terminal crimp?
Something else?

I'm pretty sure the connections were good but not ruling anything out at this point.

P.S. If anyone has any recommendations on replacement SSRs let me know. I'm hoping to avoid amazon due to their problem with counterfeits but might have to go that way anyway.

 

[doug293cz]

The burn pattern on the lead at the element connection is characteristic of a loose connection, that creates high resistance, which causes the connection to overheat. It then looks like the melted insulation allowed the hot lead to contact the grounded element enclosure, leading to an over current condition that caused the SSR to fail.

If you had this system connected to a working GFCI breaker, it should have tripped before the SSR blew out. The fact that the SSR failed leads me to believe that you don't have a GFCI breaker feeding your control panel, or if you do, then the GFCI is not functioning correctly. Do you have a GFCI? I strongly recommend that you insure that you have a working GFCI on the power feed to your controller.

As a general practice, you should check the tightness of high current screw connections periodically. The temp cycles that result from routine usage can cause them to loosen over time, leading to this type of failure.

As far as replacement SSRs, if you just avoid the "Fotek," or other unbranded/off-brand, white SSRs, you should be ok.

Brew on

 

[duncan.brown]

+1000 on needing a working GFCI that is tested regularly on any electric system, but especially a Kal clone. I had a tiny amount of water leaking into my element box. It was enough to blow the GFCI but I was fine, as were my SSRs.

I also noticed that you don’t have the recommended silicone sealant around the element in the box. when you rebuild, I’d recommend picking up a tube and applying it generously to make a water-tight seal:

https://www.amazon.com/gp/product/B004V40R2M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[gello22]

I use stainless split lock washers on the screw head side. It is impossible to get the torque necessary to stretch the screw enough to deal with the thermal cycles. The spring action of the split washer helps maintain good contact. Also a small amount of grease(vasaline) any corrosion or wort sugars getting in there will raise the connection resistance and make it a heater.

 

[duncan.brown]

One more thought looking at the high-resolution image of your connection box: it looks like there's gunk in there which suggests that contaminants may be causing you resistance heating, as @gello22 says. The inside of the good connection box on my boil kettle is spotless. The one on my HLT that failed showed signs of salt deposition from liquid incursion. I did a complete rebuild of the HLT connection box and it's still perfectly clean inside after a few brews.

I would recommend doing a complete rebuild of that connection box making sure that you have enough JB Weld on the kettle side to seal around the holes where the plate is bolted on the back of the box, then throughly silicon seal around the element after you have installed it in the kettle. Unfortunately, Kal-style boxes are not completely resistant to liquid spills and boil overs.

 

[duncan.brown]

Here's my bad box for comparison. You can see the salt residue that build up at the bottom after many brew cycles. The amount of water seeping in was tiny. For comparison, I've highlighted the stuff that I'd be worried about in your box.

For comparison, here is the box from my boil kettle, which is perfectly clean after more that 50 brews.

 

[M54B25]

Excellent information, thanks @doug293cz, @duncan.brown and @gello22!

The background I left out is that yes, I did have a leak into the connection box a while ago that I caught before it became an electrical issue. (And it was due to simply not having the element tightened down tight enough !) I took that opportunity to upgrade to the Camco 02965 and made sure the seal was completely dry but didn't add in the silicone sealant. I checked the box after each of the next few brews to make sure it was still completely dry (which it was) and that's why I feel like I would have noticed an obviously bad connection.

Either way, a good reminder to add the sealant this time. It's going in my cart with the replacement SSRs.

Additionally, I'll be adding "check screw tightness" to my checklist going forward.

The GFCI comments are slightly concerning because I definitely do have a GFCI breaker feeding the system and I make a point of testing it with the push-button before every brew day. Is there something else I should do to test it or consider replacing it anyway? I'd rather not because they're expensive, but I'd also like to not die in an effort to save $100.

My other thought is wondering if the plastic melted and the black connector maybe got close enough to contact the white and create a short there. That would trip a breaker without causing a GFI issue wouldn't it?

Again, thanks for the insight on this one!

 

[gello22]

Maybe one of the Electrical engineers will see and comment but the speed at which a solid state device can be blown by a dead short should be much faster than a mechanical breaker. There should be a test button on the breaker to test for piece of mind.

 

[duncan.brown]

Yeah, if there was no ground leakage and just a near-zero ohm short across the hot wires, I could believe that an overcurrent would blow up the solid state components in the SSR before the current overload in the GFCI breaker would trip.

 

[doug293cz]

Yeah, if there was no ground leakage and just a near-zero ohm short across the hot wires, I could believe that an overcurrent would blow up the solid state components in the SSR before the current overload in the GFCI breaker would trip.

Given the position of the wires, it doesn't look like hot to hot (or hot to neutral if this is only a 120V system) short could have occurred. Much more likely a hot to ground short. I suppose it's possible that the SSR fried before the GFCI could trip (which it should have on a hot to ground short.) I haven't found a lot of info on GFCI trip times, but did find one source that said most trip in under 100 msec. I don't have any data on how long an SSR can survive a significant over current event.

Brew on

 

[M54B25]

As an update on this, I replaced the SSR, the heating element and the wire connections. Additionally, I tested the GFCI part of my system with one of those GFCI outlet tester devices on one of the brew pump outlets and it successfully tripped my GFCI breaker feeding the whole system so that's promising.

Silicone sealant is added to the box as well even though it was leak proof in my water tests without it.

I successfully brewed a batch a little bit ago on the rebuilt system so things are looking good so far!

One thing I'm noticing while thinking and looking back: the black-hot wire burned through its insulation, but it was not disconnected from the screw in the heating element so I'm wondering if maybe the fault started at the heating element and everything went south from there.

I'll be periodically checking in on things (screw tightness/ waterproofedness etc.) but for the time being I'm leaning towards the element as the probable culprit of the original post.

Here's my current connection box. Let me know if y'all see anything wrong/ suspicious with this setup (other than the evidence of the previous leak... maybe next time I rebuild it will be with a brand new box and everything!)

 

[duncan.brown]

Looks good. I'd be a bit more generous with the sealant. You want to make sure that it seals between the front plate and the box itself, as that's where leaks can occur. Take a look at my image above and slather it on.

 

[doug293cz]

As an update on this, I replaced the SSR, the heating element and the wire connections. Additionally, I tested the GFCI part of my system with one of those GFCI outlet tester devices on one of the brew pump outlets and it successfully tripped my GFCI breaker feeding the whole system so that's promising.

Silicone sealant is added to the box as well even though it was leak proof in my water tests without it.

I successfully brewed a batch a little bit ago on the rebuilt system so things are looking good so far!

One thing I'm noticing while thinking and looking back: the black-hot wire burned through its insulation, but it was not disconnected from the screw in the heating element so I'm wondering if maybe the fault started at the heating element and everything went south from there.

I'll be periodically checking in on things (screw tightness/ waterproofedness etc.) but for the time being I'm leaning towards the element as the probable culprit of the original post.

Here's my current connection box. Let me know if y'all see anything wrong/ suspicious with this setup (other than the evidence of the previous leak... maybe next time I rebuild it will be with a brand new box and everything!)

Looks good now, but if the white wire connection got loose and overheated, there's a good chance that it could melt thru the insulation on the white wire, and then the black wire, causing a short that would not trip the GFCI, but should trip the overcurrent protection in the breaker.

I would recommend repositioning the wires so if you get melting of the insulation on either of the hot wires (due to a bad connection), that there is no possibility of one of the hots touching the other.

Brew on