Smart outlet used for espresso machine melted

Want to talk espresso but not sure which forum? If so, this is the right one.
Haskens

#1: Post by Haskens »

I've been using a CE smart outlet for my espresso machine for about 6 months now. It's been fine, but yesterday I found the machine off in the morning. I didn't think much of it, so just turned the outlet back on and used it normally. This morning, same thing, except the lights on the outlet were all off. Checked the breaker and it was on. The outlet turned on again after a while so I used the machine for my morning espresso....and then it turned off again. Touched the outlet and it felt warm, so after a while I opened it up and found it was completely melted on the one side (neutral). The neutral wire had come out, not sure if it was before the melting or after, but a portion of the wire insulation was melted too. Replaced the outlet with a regular outlet.

Not sure what caused it - either a loose connection, or the neutral screw touching the metal box (it was pretty tight in there) or an overload (I use my Duetto on 15 amp mode). Very concerned that the breaker didn't trip, but feeling lucky to have caught it when I did.

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Balthazar_B

#2: Post by Balthazar_B »

Someone here -- I can't recall who -- installed one of these, and early reports were positive:

https://iot.connectsense.com/products/i ... 0787204154

Interestingly, there are receptacles for both 20 and 15 amp circuits. You may want to do a little research into these if you want to restore smart switch capability to your machine.
- John

LMWDP # 577

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Randy G.

#3: Post by Randy G. »

The NEMA outlets I have seen are usually are phenolic(?) or other heat resistant material so that they can take heat generated by a marginal connection. We can theorize the cause, but usually this is from a high(er) resistance connection such as a lead wire that was a bit bent or not fully in contact with the connection point, connector screw not fully tightened, too short of a wire so less contact area, oxidation, etc.

The outlet has a rating of 15A and 1875 watts at 125v. Someone can do the calculations (so they are correct this time) for your voltage if that makes a difference. Few homes actually have a 125 volt feed. This is particularly true if there are other devices running on that circuit.

One solution would be to use the smart outlet to trigger an SSR in a separate metal project box.

BTDT:

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Espresso! My Espresso! - http://www.EspressoMyEspresso.com
LMWDP #644

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slybarman

#4: Post by slybarman »

Haskens wrote:I've been using a CE smart outlet for my espresso machine for about 6 months now. It's been fine, but yesterday I found the machine off in the morning. I didn't think much of it, so just turned the outlet back on and used it normally. This morning, same thing, except the lights on the outlet were all off. Checked the breaker and it was on. The outlet turned on again after a while so I used the machine for my morning espresso....and then it turned off again. Touched the outlet and it felt warm, so after a while I opened it up and found it was completely melted on the one side (neutral). The neutral wire had come out, not sure if it was before the melting or after, but a portion of the wire insulation was melted too. Replaced the outlet with a regular outlet.

Not sure what caused it - either a loose connection, or the neutral screw touching the metal box (it was pretty tight in there) or an overload (I use my Duetto on 15 amp mode). Very concerned that the breaker didn't trip, but feeling lucky to have caught it when I did.
Out of curiosity, was the wire wrapped around the screw or back stabbed?

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BaristaBoy E61

#5: Post by BaristaBoy E61 »

If your house wiring is aluminum, you might have to monitor the terminal connection periodically to make sure it remains tight.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

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JohnB.
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#6: Post by JohnB. »

Haskens wrote: Not sure what caused it - either a loose connection, or the neutral screw touching the metal box (it was pretty tight in there) or an overload (I use my Duetto on 15 amp mode). Very concerned that the breaker didn't trip, but feeling lucky to have caught it when I did.
Is the circuit protected by a GFCI breaker?
LMWDP 267

ira
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#7: Post by ira »

There is no reason any protective device should have triggered. An breaker needs excessive current, that wasn't happening, a GFI needs a short to ground and that wasn't happening either. It's possible but unlikely an AFCI breaker might have trigger if there was any arcing at the failing joint. Sadly, there is no way to protect against that type of failure. You just want to find it before your smoke detector that lets you know you have a problem.

Ira

Nunas
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#8: Post by Nunas »

Not sure what caused it
From the photos it appears to be due to a poor connection. The IR-drop across the connection expressed as a resistance of even a fraction of an ohm will heat at the current drawn by most espresso machines. Worse, this is usually a thermal run-away condition, inasmuch as the heat and arcing cause corrosion of the joint. Another respondent asked whether the outlet was connected via the screw terminal or stabbed in the holes at the back. I'd like to know that too. I have been told that stabbing provides a more reliable connection, as the female parts are springy, whereas the conductor under the screw can migrate over time. That may be, but for my money, I'd use the screw terminal with a properly-formed hook in the copper. Another poster asked about aluminium wiring. Good question. Aluminium migrates much more readily than copper. If you have aluminium wiring you need an outlet rated for such.

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civ

#9: Post by civ »

Hello:
Nunas wrote: ... appears to be due to a poor connection.
... usually a thermal run-away condition ...
+1
Too frequently seen and not forseeable, unless one takes apart and inspects before using.
And even then ...

CIV.

Haskens

#10: Post by Haskens »

Hi All,

Thanks for the replies. The wiring is copper. It was backstabbed into the outlet....replaced it with a regular old outlet and this time just went with the screws. Good to know it wasn't a failure on the part of the breakers too.

No AFCI protection, my house was built in the 60s...