SOLAR CABLE FIRES & FAULTS in ducts
ฝัง
- เผยแพร่เมื่อ 28 พ.ย. 2024
- Solar cable fires in ducts are a critical safety concern in photovoltaic (PV) systems. These fires can occur due to various factors, including improper installation, rodent damage ,poor-quality materials, or inadequate ventilation.
When solar cables are installed in ducts, they are often confined spaces where heat can accumulate, increasing the risk of ignition. Over time, insulation can degrade, and if cables are overloaded or damaged, it can lead to electrical arcing and fires.
I am a Freelance electrical engineer &, electrical trainer for hire and I work all across the UK
Specializing in industrial electrical installations, process electrical engineering & motors and control systems
! if you can find me you can hire me . I am “ jamie blatant sparky” on both linked in and Instagram so drop me a message on there
Alternatively my company is Rt industria Ltd and our website website is actualelectric...
Great video, never seen anything like it. When I installed my solar, I made all the connections on the roof where nothing can catch fire. Cables a routed 10cm (4") apart in the attic so in event of rodents they can't make s short circuit. There were a couple of fires in my country, mostly on farms and I suspect rodents in combination with improper installation.
Good reason why positive and negative isn't allowed in the same pipe here.
I would have through + and - would be in seperate conduits to start with ...
Nice fault mate. I done a lot of work on external security systems and seen that effect with voltages from 5Vdc to 24Vdv at milli amps of current. It’s the magic of DC that basically magics the metal away when a current path is established due to water. Electrolysis moves ions from the positive to the negative. Natural salts from the groundwater will improve its conductivity no end and once the reaction starts it will keep going till there is nothing left. It doesn’t happen on AC as the changing polarity puts the ions back!! Automotive wiring suffers similar failures due to water ingress. All the best.
OK.. at mA.
That was instantaneous arc.. plasma vaporising the copper, tin, plastic, maybe water.
Big volts and high current fault there. One flash and then ash.
@@BTW...Aye, for sure it would have been quite a flash. The higher voltages and current will certainly do more damage. My point was that even a low voltage and current the DC effects are superb compared to AC. Cheers
Agreed very interesting.... From the view we have it looks like the duct is pact.... From your view do you think they left enough space inside? Fill factor is 40%?
Interesting video Jamie. I agree that PV Ultra would be a better cable to use now but if that install was from 10 to 15 years ago. I think PV Ultra from Doncaster has only been out for a year or so. Currently they offer 2 core and 4 core upto 10mm CSA and they do a SWA version aswell.
Agreed, but the panels are much more powerful now, fires are becoming more regular
What is the rated insulation voltage of those PV cables? 1.1kV?
There is your problem... idiots using any standard cable rated for 240/415 V circuits that has a lower insulation rating.
Could be worse... some idiot using cable designed for 12/24V automotive use.
So DC AFDD’s don’t exist yet?
Is pv ultra rated for permanent submersion?
@@zjzoznyou can get panel disconnects that you install near the panels, they will disconnect under fault scenarios. They need a separate pilot signal I understand.
Even pretty clean rainwater will quickly get contaminated with metal salts from the cable as electrolysis starts kicking in
Lol, learned something & had a laugh, cheers fella 😆👊
Anytime
Would you be better off with a direct burial cable?
Terrifying, considering the PV solar cables i have in copex running through people's houses! I would like to see a 5 core SWA with DC colours and cpc used as standard. The cpc is now essential as the next big thing will be the breakdown of insulation in the panels themselves. The simplest solution is to earth the PV subframe and do an insulation resistance test from earth to negative and again to positive, which the fluke does not mind on 500 volts.
Oh FFS... copex is NOT insulation rated for PV installation. That shit copex doesn't even have an insulated or multi-strand Earth conductor.
Output voltages from PV arrays can far exceed 500V DC.
Furthermore, 500V insulation resistance test should be at 1kV.
And what sort of idiot doesn't Earth PV frames?
SWA? There goes your current rating. Do you like paying for cable with a larger than needed gauge/cross sectional area, derated so much because it can't dissipate heat as well as a correctly installed correctly rated cable?
SWA has limited applications to protect against mechanical damage. It's heavy and expensive. DC colours too? LOL... I bet it would be confusing for some when they encounter only 2 colored wires in a control panel - Black and Green/Yellow.
Better to ask for something that matters - ONLY trade qualified electricians work on equipment and installation and testing in accordance to Code... and people that can be held accountable for their sub-standard work.
Sorry... error. I read copex as meaning that shitty Romex cable.
Copex I've seen is a thin steel conduit/ paper lined ... sometimes has a plastic jacket - not very resistant to crushing or damage from some butcher drawing in wires rough as guts.
@@BTW... Really the copex is just a way to neatly organise the double insulated PV cables neatly when coming from the roof into the fireman's switch (shunt) in the attic. Where we are you have to have automatic disconnection within 1.5 metres of entering the house, wherever you choose to do it. The problem then is getting the cables back to a safe place to site the equipment, utility room is my preferred location, unless there is a garage of course. Equipment placed outside does not do well in Ireland.
And I am old enough to remember identifying DC with red and white in Pyro.
DC cables coming from PV do not get power from "both ends". The issue is PV is DC, and thus has no zero-crossing like AC does, so the arcs can get enormous! The inductance of the PV array can generate a huge arc. (I am an EE)
They do get glued from both ends on large scale as you have combiner boxes , I assure you it gets a bit from both ends
@@Actual_electrical_content The inverter side does not put out power, and in fact; most inverters have arc-fault detection which will dump the load to reduce the change of fire for a loose connection that is arcing.
@@Ingineerixyour failing to recognize previous technology, every thing your saying applies to modern systems but it was not always like that , this is a 15-20 years old solar farm working on much more basic DC technology
These pv strips are connected in parallel on inverter, so effectively powered from both sides untill all of them break.
@@Actual_electrical_contenttypical ‘engineer’ probably never physically made off a cable in his life
Never understood why rodents love to nibble on pvc in the first place... whats all that abt!
The fuses didn't blow?
Eventually
Why wasn't the conduit dug in properly and incased in a concrete culvert for a extra layer of protection cheap work sparky's must work for Amazon or Temu
Because dc cables in pv are never protected. Ground leak, insulation fault? No, never heard! Too expensive for dc circuitse with unstable voltage.
I doubt the inverter would keep back feeding like that, they automatically do insulation tests, can’t see that passing with copper sitting in water or shorting. Yeah the other end will burn all the ways back to the panels eventually.
They do get glued from both ends on large scale as you have combiner boxes , I assure you it gets a bit from both ends
Why don't just use multi core armoured and put all pos Ve in one cable and neg Ve in the other cable. Seems obvious.
At least put two ducts and separate polarity in each duct
@@freddiewithers9617If all those positives or negatives melt together I’m not sure you get a better outcome, could end up with currents well beyond what switchgear is designed for?
@@edc1569 The arc fault condition which caused the cables melting together would be much less likely since the different polarity cables would be in separate ducts. This fault would be extremely unlikely if the different polarity cables were spatially separated.
@@freddiewithers9617you can still get a fire if the strands get damaged even on a single conductor.
No rodent will get up such a small space to chew cables. The 'rat' that nibbled the insulation has 2 legs... the butcher that pulled them into the conduit.
That shitty conduit is NOT suitable for direct in ground installation.... simple as that.
You are dealing with DC at higher than typical voltages. Once an arc propagates it does not self extinguish like an AC arc fault. I've seen a PV DC output cable maintain an arc easily across a 300mm air gap, once started. Try yourself if game... spark the cables and draw apart on a sunny day.
You find water in poorly installed conduits. The 'green' you see could have come from the burning of the PVC insulation and conduit. Combustion products of the plastic create highly corrosive compounds.
Do it right - Do it once.
Single insulated wire (we call it 'building wire' despite the fact it isn't appropriate for building installation) in a pathetic thin wall conduit, more apt for a bloody LV car wiring loom, buried in the ground or subject to mechanical damage is NOT an approved method of installation by any standard. I bet the bodgy bastards that did that didn't even use correct conduit glands, met IP ratings, saddled correctly, protected against abrasion or considered appropriate depth when they buried it in ground. I bet they didn't even derate the cables correctly.
It's a waste of good materials doing a shitty sub-standard job like that.
I'd consider failing and condemning the installation, and then rip-out and start again using the correct materials to be compliant.
It’s dc mate, it’s like wiring up your Lego, nothing to worry about ;)
@@edc1569 LOL Lego. Try breaking an arc. 😉
It's NOT Phase OR neutral it's Plus and Minus
PV Cables are NOT made with PVC
H1Z2Z2-K has EPDM as sheath.
PVC these ones are
Why not use multicore cables for point to point in robust ducts to equipment housing etc. allowing for some redundancy ( spare cores should you loose a circuit and have to divert a function) running single core in that type of duct seems bonkers…..not thought out very well but this is indicative of new technology and its applications …..
AFDD
Pull a duck 👍
Quack