Why do ballasts melt plugs?

I was at a friend’s house last night. She had bought two used electronic 1000 watt ballasts off ebay months ago. The first one immediately tried to catch on fire when plugged in. The second one seemed ok. Now, a few months later, I just noticed that it has melted one side of the plug and the timer it was plugged into. I had seen old magnetic ballasts do this, but never an electronic one.

Obviously that ballast is not getting used again, but what exactly is happening to make ballasts melt plugs like that?

A poor connection somewhere that is arcing and causing excessive heat. It could be inside the plug assembly or the external contacts or anywhere else the power feeds.


Also loose electrical connections create a lot of heat and melt at that point.

These blade conectors were not crimped properly and that is the result.


Loose or poor electrical connections cause heat, which increases resistance, which causes more heat, which increases resistance, and this self-reinforcing loop keeps going until a breaker trips or something melts or catches on fire. I’m a big fan of flir-type thermal cameras to catch these sorts of things before they cause a fire or downtime


Heat is created when too much amperage flows through too small a conduit. A loose connection doesn’t have enough contact/the power doesn’t have enough conduit to flow through, creating resistance.

Then what Greenbuggy described happens.

This is similar to what happens when you plug a lot of amps into a small guage extension cord and the cord heats up.

This a danger when it gets to the point of melting/ causing a fire. But its also important to know that if your wiring is getting warm/hot, even if it is not to the point of being dangerous, you are putting stress on your appliances that plugged in, especially anything with a motor.

Heat is bad, avoid it. Make sure you always have the proper guage wiring/cords and that all connections are solid so that your power has a clear path and doesn’t meet resistance.


Did you plug in a 110v ballast into a 220v plug?


also make sure you have proper electrical wire and breakers to support this…im talkong about the wire inside the wall going to the box

i had to run brand new wires and new breakers for my lights only

othwrwise id trip the breaker or melt wires or ballast


The wiring is solid, as far as the house goes. I have seen a lot of melted plugs over the years.
This was just the first that wasn’t on an old magnetic ballast.

I had a couple plugs melt and a few outlets also. For me though it’s always been through light controllers. It seemed to happen to the one with the plastic cases(titan/ autopilot style) vs the metal cased ones. I’ve had multiple plugs on multiple controllers burn. I chalked it up to loose connections inside the controller or undersized wires. I’ve found melted/burnt wires inside a light controller when I went to swap it, talk about lucky. Only found that sucker doing some preventative maintenance.


That ground is shity also

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shitty cheap gray metal timer boxes FTW

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