The best early video footage of the Grenfell Tower fire is found on Chox Noris YouTube page, starting at 22 minutes into the fire on the East facade. Link These are truly worth a viewing to see how the fire spread.
Sky News provides the best aerial video, including a breif view of the East facade 4th floor, post fire: Link
Tom Clarke, Science Editor at UK Channel 4 has some of the best fire investigation reports. Channel 4 works for me here in the US over the internet but you may have to try different browsers. Link
I still have questions about the Electrical supply at Grenfell Tower and hopefully someone, ScottyUK, can enlighten me.
BACKGROUND
Extract from an email sent on 13th May 2013 by Shah Ahmed, Chair of the Grenfell Tower Leaseholders Association, to Robert Black at KCTMO and various RBKC councillors and TMO officers:
“Continuous Power Surges in Grenfell Tower".
There have been two weeks of power surges in the building, most notably in the early hours of the morning and throughout the evening and night time. Electronic apparatus are seriously affected by these surges. Computers are turned on and off; lights continually flicker becoming very dim and extremely bright in the space of a few seconds.
On 11th May 2013 at 9:05pm we had numerous power surges in the space of a minute, and in that process my computer and monitor literally exploded with smoke seeping out from the back and the smell of burnt electronics filled our entire computer. My monitor also fused at the same time. When I called the TMO out of hours service the standard textbook response was given to us that I was the first one to report such a problem and I was made to feel like a fool reporting such an issue, which resulted in years of data being lost forever.
Please note if the power surges continue at Grenfell Tower, it would be very dangerous and costly because it is interfering with electric and electronic items in the household, including the telephone line, television, fridge, washing machine, computer etc”.
Grenfell Action Group Blog - "GRENFELL TOWER – FROM BAD TO WORSE" Despite the fact that these dangerous and highly alarming incidents were reported to the KCTMO on 11th May no serious action was taken until the problems escalated out of control on 29th May 2013.
• Decisive action was only taken yesterday after highly distressed residents descended en masse on the estate office to demand action. They had woken to find smoke issuing from various electrical appliances in their homes, including the light fixtures, and descended in panic to the estate office to demand help and assistance. Emergency electricians who attended later in the day were finally, it seems, able to identify the source of the problem. An emergency temporary electrical by-pass supply has been provided and the necessary follow–up works will be carried out in the near future.
• Grenfell Tower residents are demanding an emergency meeting with RBKC and TMO officers to fully explain what went wrong with the electrical supply, and why the TMO failed to respond with appropriate urgency. This meeting should be arranged as a matter of urgency.
• Officers attending the meeting should be prepared to explain why electrical engineers who ordered the planned power cut in Grenfell Tower between 08:30-17:30 on Saturday 18th May failed to identify and rectify a serious and dangerous fault in the electrical supply at that time.
16 July 2013 - THE ROYAL BOROUGH OF KENSINGTON AND CHELSEA - HOUSING AND PROPERTY SCRUTINY COMMITTEE
As a matter arising related to A5, Mr Maddison reassured the Vice Chairman that expertise from qualified electrical engineers had been used from the outset in establishing the cause of the Grenfell Tower power surge. The officers’ view remained that it had been caused by an arced incoming mains cable.
A fault has been identified on the incoming mains supply and a repair has been carried out to a faulty cable. There have been no further surges since this repair was completed and further tests have been carried out on the mains.
• Ongoing monitoring of the incoming electrical supply and we are investigating whether there are other factors that have contributed to the surges.
• Full renewal of the rising electricity main is planned to commence on 7th July. This work will include the installation of surge protection to give additional protection to the block.
In a later report to the council - Mr Maddison reported that Zurich Insurance, the company used by the TMO, had reviewed all claims for damage and had confirmed that the TMO had taken appropriate steps to ensure the power supply infrastructure was in a reasonable state and the TMO therefore, had not been negligent and was not liable for loss or damage to tenants’ equipment.
TMO officers had met residents and advised them by letter to claim for damage via their own home contents insurance. As a token of goodwill and in compensation for disruption, a payment of £200 had been made to each tenant. Mr Maddison said the TMO recognized this might not cover the cost of lost equipment.
QUESTIONS
Based on descriptions given by the residents of smoking fixtures and appliances, including Washing Machines & Refrigerators AND KCTMO's Mr Maddison, assertion that the electrical fault was identified as 'arching cables from the incoming mains'; is it just as, or more likely that the damage to appliances was the result of under supply as over supply? While power spikes might cycle too fast to trip the built-in fused plugs provided on plug-in appliances, wouldn't a persistent over supply have tripped the fuses, whereas an under supply would result in a persistent draw and heating?
I am assuming full or partial start capacitor damage could arise from such events but is this reasonable? And short of testing the capacitor on every large appliance, is there some other means of assuring that a still functional appliance isn't a damaged appliance & a fire waiting to happen?
Very Speculative Questions
When KCTMO's Mr Maddison informed the HOUSING AND PROPERTY SCRUTINY COMMITTEE that "Full renewal of the rising electricity main is planned"' wouldn't this indicate that the electrical problem was located on the property-owner side of the electrical supply?
If the electrical failure was on the owner side of the supply, and regardless of prior efforts to locate the source of the electrical hazard, which failed; doesn't it still remain the Landlord/Owner as the party responsible for delivering well regulated power to the junction box in each apartment and hence, for the damaged property? Fortuitously, Zurich Insurance was no longer the insurer when Grenfell Tower burned but if the Landlord/Owner and vis/vis Zurich Insurance snookered the residents on their insurance claims, and in so doing, failed to perform due diligence, leaving crippled appliances & long-term fire hazards in place, wouldn't Zurich even now be liable? EXAMPLE: When earthquakes strikes and liquor bottles fall to the floor, some but not all will break but since ingesting even slivers of shattered glass is a safety hazard, the insurance company compensates for all the liquor, broken or otherwise. So did KCTMO commit insurance fraud by omission of particulars to Zurich or did KCTMO & Zurich commit insurance fraud by Zurich writing KCTMO a get-out-of-jail-free-card? Does the UK Insurance Industry really decide Insurance Claims strictly on the basis of Negligence? It certainly wasn't an act of god. Maybe Gremlins but you can't blame it on Jinnis. If for instance on May 29, 2013 multiple flats in Grenfell Tower had gone up in flames because of the catastrophic electrical failure and people had died, would Zurich Insurance still argue that KCTMO bore no liability?
The electrical fault has all the indications of a high impedance or lost neutral connection. The net effect of this failure mode is that the single-phase supply to each unit, which is derived from a 3-phase intake, is no longer fixed at 400/[√]3 = 230V. The voltage appearing at the individual units could range somewhere between zero and 400V, and the exact voltage is determined by how the overall loads on each phase interact with each other. Electronic loads would typically burn out / catch fire fairly rapidly when faced with a gross over-voltage. Rotating loads such as motors would probably tolerate if for a bit longer prior to blowing a line fuse. The problem isn't confined to capacitors by any means.
I can't answer any of the questions about insurance and liability for legacy problems.
ScottyUK, " The voltage appearing at the individual units could range somewhere between zero and 400V, and the exact voltage is determined by how the overall loads on each phase interact with each other."
Is the voltage a sinusoid from zero to +/- 400? or that the voltage delivered could range from zero to 400 (I assume +/-?
I have since been reading about English Tort Law and it does appear that Negligence rather than Responsibility is a requirement for liability in the UK. So long as KCTMO hired a qualified Electrical Contractor to troubleshoot the fault, regardless of failing to identify the problem, they exercised due diligence and are not liable. I think in the US it could go quite differently, considering more than a 1/3 of the flats were affected by some kind of loss and deferred maintenance had been going on for years.
It is not widely discussed but more and more private power generation when supplied to the grid, especially PV systems are proving problematic in the UK and power surges are one of the consequences.
I'm from a generation background and I'm not a great believer in embedded generators replacing central generating plant, but I don't see this as being a problem on the generation or transmission grids. This is almost certainly a problem within the building - either the main distribution LV infrastructure, or potentially with the building's LV substation if the building has a dedicated intake from the HV utility system.
Dik,
The voltage will be sinusoidal, but it's magnitude is determined by how the connected loads interact with each other and that will vary as loads change (i.e. things switch on and off, fuses blow, things go bang, etc). It's probably easier to explain with a couple of diagrams. They're not perfect for the task but I'll try to explain around them:
In a healthy electrical system the line-line and line-neutral voltages are defined by the transformer which comprises of three windings, each of 230V but with 120° of angular (time) displacement between them. This angular displacement results in there being 400V between any two lines, but 230V between any line and the neutral point. In the UK, residential supplies are connected between one line and the neutral point.
If we can assume that all the loads are connected to the neutral, but that the neutral conductor breaks or develops a bad joint somewhere near the transformer. The voltage between lines is still 400V, because that's determined by the transformer windings. Without the connection back to the transformer neutral point there nothing to force the line-neutral voltage to be 230V. The voltage between line and neutral will be determined by the relative impedances of the loads connected between each line and the neutral, so a heavily loaded phase will see the line-neutral voltage collapse, while lightly loaded phases could see something approaching the full line-line voltage of 400V.
Zurich's response wasn't really a get-out-of-jail-free-card. It was more a judgement that KCTMO had a defensible position so if they refused to pay out against the claims, the courts were unlikely to rule against them. Don't like like the mindset, but can't really see anything fraudulent about it.
Scotty's correct diagrams may be a little confusing due to the three phase aspect so I've simplified them to a single phase situation.
A normal single phase installation with each phase being exactly half of the 440V supply because of the center tapped neutral.
With a faulty neutral often caused by a loose connection or corrosion or both you no longer have a rigid half of the 440V across the two loads. Instead you have something....worse. You have various voltages depending on the individual loads connected at any moment.
You can see the light bulb will take a beating. Typically this would just be a bright flash then the circuit would be open. However if the bulb was instead something with real mass like a small motor it would heat up in a few seconds to a fire starting temperature.
Picture the complexity of a large apartment complex where perhaps a thousand devices are in the mix. You typically get less of a voltage difference just because of the averaging of a great many typical loads. What you get though is perhaps 180V and 260V which can actually be more insidious with overheating and fire starting as it can allow things to overheat slowly enough that circuit breakers fail to trip as they would with a large overload.
Thanks Keith ("itsmoked") - that's a great description of faulty multi-phase power for non-electrical engineers like myself. (I had to do a bit of power and electronics as part of my undergraduate Civil / Structural Engineering degree; unfortunately, I am colour blind, so more often than not, I would be hooking up the wrong wires and / or using incorrect resistors, so most of my lab work ended with a release of the magic blue smoke.) These days, I stick strictly to low voltage hobby electronics (< 12 V), and I use a multi-meter to test every component before hooking up the power supply.)
The litany of professional mis-management at Grenfell Tower is just gob-smacking. It seems quite likely that defective power could have been a causative factor in the initial fire, and the on-going issues suggest that it was only a matter of time before a significant apartment fire broke out. This in itself is bad enough, but compounded with the choice and design of cladding system, a small manageable fire quickly became a catastrophe.
To make matters even worse than you can imagine them to be, read a few days ago that these muppets at RBKC replaced some parts of the PIR insulation with cheaper Kooltherm phenolic based insulation from Kingspan, which apparently has no fire resistance rating at all.
No, I did not. If I were a freshly minted electrical service repair technician though, my take away would be that if someone is reporting power surges, because that is what they can see with their eyes, then when a neutral fault is found, it also means that other electrical apparatus were experiencing..., what does one call it? Brown power aka low voltage? It is a critical, missed detail of the May 2013 power failure. In earlier discussions here with ScottyUK regarding the Fused Plugs in the UK, I struggled with how a Power Surge could result in the slow degradation of an appliance leading to a fire, brown outs made more sense. Now I know that power surges & brown outs happen simultaneously during a neutral fault.
itsmoked sketch made all the difference. It seems to confirm my thoughts that more widespread damage could have taken place in 2013, more than just to the 45 flats on the upper floors but via a "slow burn". It just wasn't catastrophic to other appliances..., yet. I really appreciate ScottyUK and itsmoked informing us on the UK power grid. While there has been a great deal of reporting on the Power Surges at Grenfell Tower in 2013, there hasn't been any real discussion of how the 2013 electrical problems may have contributed to the initial fire that destroyed the tower. I thought it worthy of examination here. Perhaps the recommendation in the 2008 Master Plan for Lancaster West to demolish Grenfell Tower was a better plan after all. Link
So the next question for ScottyUK & itsmoked is, how likely is it that an electrical contractor replacing the electrical riser at Grenfell, doesn't at some point tell KCTMO's Mr. Maddison, speculatively or assertively, that the whole building needs to be rewired. In my experience a contractor never fails to point out additional work if it really is needed.
I had somewhat down played witness statements because some were just bad reporting, some activist reporting and others are probably the result of language barriers but embellishments have also taken place. For instance, Maryann Adem on the Forth Floor, Flat 14 (one bedroom flat East facade/next door)“The fire was small in the kitchen. I could see it because the flat door was open. There was no alarm.” - Truth: There is absolutely no means possible to see the refrigerator from the flat entry door. So does she mean from the kitchen opening? Is this a language barrier/simplifying or is she embellishing? A number of Grenfell Tower victims have since embellished their version of events. Being an investigator, taking witness statements must be a very frustrating job.
Sajad Jamalvatan, a biomechanical engineering student, moved into one of the newly constructed "Hidden Homes" flats on the third floor of Grenfell Tower in August 2016; saying the newly installed electrical meter often made a strange buzzing sound at night and constantly had to be topped up with money. "I went to the basement once and I saw a huge mess in the basement. So much wiring." Is Sajad just taking his place in the limelight or did the noise from the electrical meter actually indicate there was still an electrical problem at Grenfell. After ScottyUK & itsmoked input, I'm now curious as to the proximity of his 3rd floor flat to flat 16, one floor above where the fire started.
All the electrical problems were late evening to dawn, when the electrical grid has a surplus of available power. The 'problem' could have been well within supplier & building code standards, except not for a building that was badly in need of rewiring. If the Council had known that Grenfell Tower needed rewiring along with all the other needed upgrades, it probably would have meant the demolition of Grenfell Tower, no matter the political fall out.
I wonder if the 2013 electrical problems will be part of the Public Inquiry. KCTMO's Mr Maddison's statement to the Council that a problem was found with the "Incoming Main" is suggestive that the problem was on London's UKPN supplier side. Maybe he was telling the Council what they wanted to hear. If not, then it is somewhat misleading. A more comprehensive explanation might have resulted in a closer examination of the building wide wiring by the refurbishment consultants, Max Fordham and concluded the wiring was at the end of its service life. Many of those who are demanding a wider Public Inquiry, want the relationship of the RBKC Council and KCTMO investigated on grounds of a more political nature but what about how the residents of Grenfell Tower may have contributed to the loss of life during the fire?
Grenfell did have a Floor by Floor Fire Alarm system. Soon after it was commissioned, there were incidents when the fire alarm was activated because a tenant had left their flat to smoke a cigarette but instead of going downstairs & outside, they lit up in the common area on their floor. Smoking in the common area was setting off the common area smoke detector. The smoke detector signal, then shuts down all the boilers in the basement, feeding Grenfell Tower & the finger blocks of Lancaster West Estate and activates the positive air ventilation system. KCTMO also had a problem with youth who would hang out in the stairwells, sometimes wanting a dark place, they would purposefully damage the stairwell lighting. KCTMO had staff assigned to check stairwell lighting on a quarterly basis but some of the female estate managers reported being intimidated by Anti-Social elements and not being able to complete their surveys. Grenfell also had a problem with tenants dumping appliances & mattresses, etc (Fly-tipping)in the main lobby and around the premises. So it is fair to question if the reason the fire alarms/smoke detectors & emergency ventilation system didn't work as designed, has more to do with certain tenant "Modifications" than a failure by KCTMO.
