Can someone explain to me what happened here? Pic related is

Lower screw was bit loose, wire started arcing and the heat burned/melted the plastic?

>>1163265
That is possible, although i dont understand how iz could become lose on its own. I could juts replace the fuse and the wire and see if it happens again.

>>1163263
Is that flex?
Many small stands of fine copper wire?
Breaker probably isn't designed to work with flex and certainly not with such a small csa flex.
Did you crimp the ends?
Crimp some bootlace ferrules on the conductors before you screw them down.
Did you follow the torque spec for the breaker? Breakers often have a torque you have to meet when tightening.
Maybe on the other hand it was too tight, you broke some of those small strands by tightening or when you striped it to begin.
What loads are we talking here, in a greenhouse so heaters? Grow lights? How many amps? Cable looks like it couldn't take more than 4 or 5.

Heat makes metal expand, current makes heat. Cycling current on and off makes the connections expand and contract, they work loose over time, as the connection gets worse resistance increases, heat increases, spirals out of control.

Summary: Crimp on ferrules or use solid core wire. Tighten sufficiently and check tightness periodically.

>>1163279
Its solid copper wire, no flex.
The loads shouldnt be too much.
Its several 8 A tops. The wire should be able to handle 16.

What baffles me is that the earlier wires didnt burn while having to suffer. More current than this one. They are identical thickness though.

It happened overnight btw, could be when the heaters went on.

>>1163285
Heaters??
That doesn't sound like an 8A circuit to me, senpai.

File: 20151105_105405.jpg (2MB, 2048x1536px) Image search: [Google]

2MB, 2048x1536px

just replace circuit breaker and re-terminate.
connectio s can become loose over time with variations in temperature. no big deal...
pic not related..

>>1163287
Two 500W heaters =1000W/240V = 4 A
Right?
Plus 210 Watt lighting
280Watt Pumps
80W airstones
180Watt ventilation

Will be about 8 A, no?

>>1163289
Thank you, famalam.

>>1163263
wire came loose and arced. shit happens. if it was a current issue the breaker would trip

>>1163295
Seems like ventilation overkill, you're just pumping out the 1000w heat at night. Get a fan controller.

Richtig, einfach schlechte verbindung - hoher übergangswiderstand - erzeugt Hitze, udn bei starker belastung dann auch mehr Hitze.. schmorrt

>>1163301
The breaker was tripped anyway but i guess its because of the heat.
>>1163316
Ventilation is for air exchange on hot days, its never on at the same time as the heater.
>>1163300
Also einfach austauschen, noch mal neu verdrahten und auf das beste hoffen?

>>1163285
>The wire should be able to handle 16.
bullshit can that wire handle 16A, 1.5mm single core can handle 16amp but that doesn't account for tolerance or line impedance. 2.5mm twin +e would be better here

>>1163273
It happens over time, gets worse with vibrations.

In big factories they go around every now and then to tighten all of these kind of screws to prevent these problems.

At least that's what a retired electrician once told me.

>>1164399
This.
Source: that's my job

Thats 1.5q dont load it more then 13A. But that looks like the screw got loose, arc, and burned the wire. The screw can get loise with incresed load over time.

>>1163273
You need to tighten the screws every 2-3 years. Load variations cause alternating heating (dilating) and cooling of the connections. Also, vibration.