Surge Protector: But who protects the surge protector?

[alfsauve]

Again at my final gig as an in-house video and lighting guru. Solar related only obliquely.

One office on campus got a new fancy fax machine. Large warning in the installation guide says to use a surge protector to keep the machine safe. They got a small plug in unit. Only two problems with their choice. a) It had two outlets b) They plugged in such that it covered up both wall outlets.

Why is this a problem? a) It allowed people to plug in other things to the surge protector. b) There weren't any other easily available outlets in the room.

SO, the very first night the contract cleaning crew plugged in their industrial, brush, commutator motor, driven vacuum cleaner. They plugged it into the same outlet as they always had, except that there was now a surge protector, with an available socket on that outlet.



Evidently, to answer my question, there is nothing to protect the surge protector.

Lesson: Don't use surge protectors for things other than electronics. Heavy, arcing motors play havoc on these devices.

 

[time2roll]

Need a second wall outlet for the cleaning people. Cover the second outlet of the protector.

Very possible the protector prevented damage to the equipment.

 

[Bud Martin]

Again at my final gig as an in-house video and lighting guru. Solar related only obliquely.

One office on campus got a new fancy fax machine. Large warning in the installation guide says to use a surge protector to keep the machine safe. They got a small plug in unit. Only two problems with their choice. a) It had two outlets b) They plugged in such that it covered up both wall outlets.

Why is this a problem? a) It allowed people to plug in other things to the surge protector. b) There weren't any other easily available outlets in the room.

SO, the very first night the contract cleaning crew plugged in their industrial, brush, commutator motor, driven vacuum cleaner. They plugged it into the same outlet as they always had, except that there was now a surge protector, with an available socket on that outlet.

View attachment 123657

Evidently, to answer my question, there is nothing to protect the surge protector.

Lesson: Don't use surge protectors for things other than electronics. Heavy, arcing motors play havoc on these devices.

Did it blow up right away the minute they turn on the vacuum cleaner? The melt plastic around the male Hot pin of the surge protector suggesting there is some kind of poor contact resistance that has been happening for quite a while. What is the model of this PowerTracker surge protector?

 

[alfsauve]

I don't think that sacrificing the protector was part of the plan, but yes, the protector having a melt down might have saved the fax machine from undue "noise" on the line, even though it was on the load side and not the supply side.

It was a slow melt down with acrid smelling smoke. Could have been the vacuum was in excess of the rated current for the protector but because it was an brush/commutator induced load it didn't trip any protection within the surge protector.

Sorry don't have the model number.

Yes, provide for your cleaning crew and cover up any unused outlets on protectors.

 

[Duck1021]

That appears like the contacts on the cord end for the floor cleaning equipment had high resistance. This can happen easily if the cord end is exposed to cleaning chemical and corrodes. This make a high resistance connection that heated up with the current passing through it.

Power (heat at the connection) = Amps squared X Resistance

As far as the surge suppressor inside of this device, it's just a metal oxide varistor (MOV) that decreases resistance as the voltage applied increases. These are designed to dissipate voltage spikes as heat. They're rated in the number of Joules of energy that they can absorb.

TLDR; The noisy brushed motor definitely introduced noise in the line, but nothing that will cause the MOV to fail. This was a failure of the contacts due to a poop connection and high current.