Though of little use to the conversation at this point, here is a nice 360 degrees shot from the walkway between the new Academy building & the new Sports Center. It give a nice lay of the land. 180 degrees from Grenfell Tower can be seen an electrical station between the Academy on the left & the Sports Center on the right, with Verity Close housing behind and the pathway leading to Silchester Road veering off behind the Academy. Link Not sure what the little sputnik on the park green is for but all in all the line of sight suggest, Leadbitter must have had some interaction with the Grenfell power grid.
Modern practice is to put the substation in a separate structure as shown in your link. In the 1970's and prior to this date it was still common to have transformer pens set into the building facade and for the switch room to be within the building envelope. I believe the industry moved away from this as a result of transformer fires, or a perceived risk of transformer fires.
If the 2013 problem was truly just at the top of the building, there a couple of possibilities.
One is that there are multiple feeds into the building and that one feed supplied the upper floors but not the lower floors. Open neutral could then have been most anywhere.
The other possibility, and far more likely to me, is that there's a single feed that goes up the building. My guess is that every few floors there's a distribution panel that feeds the panels for the individual units on a hand full of floors. Maybe one distribution panel every 3 or 5 floors to feed the units on that floor and the floor or two above and below as well as a pass through feed to the next distribution panel up the stack. The connection to the neutral at one of those distribution panels would have been what failed. Everything above has problems, nothing below.
There is anecdotal non-technical discussion on the internet of a temporary 'bypass' being made during repairs. That would certainly be easier to achieve with accessible boards within a building than bypassing a damaged neutral in a cable.
There is a point at which I came to the conclusion that Grenfell Tower was always intended to be part of the facelift to the area begun with the Academy & Sports/Leisure Center projects (KALC). The original design of the KALC project called for a (CCHP) Combined Cooling & Heating Plant aka Co-generation Plant. It is a requirement of certain projects in the UK, maybe just London to explore and/or develop a CCHP that is capable of supplying heat & power to the district in which the project is situated.
Some of the problems a CCHP built by the KALC project were, the small footprints of the Academy & Sports/Leisure Center, the district (Grenfell Tower and the 3 Lancaster West Finger Block Flats) being the largest user of the CCHP and the amount of waste heat lost in supplying the energy to the district without doing an extensive refurbishment to the district heating system. There was also the concern of finding a long-term plant operator that would view operating a plant capable of only marginal surplus power sales & profit marketable. I got the impression the downside was driven home purposefully to justifiably eliminating the CCHP from the KALC project.
One idea the Energy Survey didn't look into was the RBKC Council providing a long-term lease of the basement at Grenfell Tower to the KALC project and in turn the KALC Project leasing the CCHP plant back to KCTMO, the Council's Residential Property Management Organization.
The RBKC Council & KCTMO were hamstrung when it came to spending on large council owned housing projects. Even though they had over 200 million in reserves in the Council Owned Housing-Housing Revenue Account, much of that was weighed against existing debt and the difference between the debt and the reserve, represented the total amount of borrowing the Housing Revenue Account could exercise if needed. They could borrow about 18 million. The Council was also restricted to using only money from income & rents generated in the Council Owned properties to fund the Housing Revenue Account.
If the KALC Project had leased the basement at Grenfell & leased back the CCHP to KCTMO, the Council would have been able to seemingly inject Council money from outside the Housing Revenue Account into a project that would have benefited the KALC project while meeting the District supply goal and solving the problem of replacing the boilers at Grenfell Tower without the Housing Revenue Account having to make a gross expenditure but one over time. KCTMO would sell discounted heat & power to the Academy & Sports/Leisure Center, be able to supply cheap power & heat to the district while still charging at a profit but also bear the responsibility of acquiring an interested operator. The Housing Revenue Account, not having to pay upfront costs for the new boilers & power generator plus the whole basement electrical would have been reworked, would seem to have been a Win/Win/Win.
But perhaps I give too much credit to the RBKC Council that they wouldn't have still done Grenfell's facelift on the cheap.
While not directly relevant to Grenfell Tower, Australia's "Four Corners" current affairs show ran a story last night about how much PE-core cladding is installed in Australia. (We had our own near-disaster with the Lacrosse Apartments fire in Melbourne in 2014.) I suspect the situation could be similar in many other countries.
In the wake of the tragic Grenfell Tower fire in London, reporter Deb Whitmont investigates the risk of flammable aluminium cladding in Australia & the dangerous legacy of failed regulation in the building industry. #4Corners
ABC TV Broadcast 8:30pm Mon 4 Sep 2017. Published 12 hours ago, available until 9:17pm on 27 Sep 2017. File size approx. 358 MB
Another note on open neutrals and high voltages.
Putting together the comment that the diversity of the large number of loads would somewhat limit the overvoltage on one phase, and Keith's sketch.
In the sketch, replace the 100 Watt lamp with 4 25 Watt lamps. Same over voltage on the lamps but the weakest fails first.
Now we have 75 Watts in series with the tea pot and the voltage rises. The next weakest lamp fails and now we have 50 Watts in series with the tea pot and the voltage rises further.
The point is that while diversity may somewhat limit the original overvoltage, as devices progressively fail, the voltage progressively rises.
It is a situation with a natural tendency to become worse.
Actually the effect is different depending on whether one phase is lightly loaded with respect to the other two or if one phase is heavily loaded with respect to the other two.
With one phase lightly loaded the voltage will drop slightly on the other two phases and the devices on one phase will tend to fail.
The voltage on the high phase will approach approximately 400V/2 x 1.73 or 346 Volts.
If two phases are lightly loaded and devices on both phases begin to fail the voltages will approach 400 Volts.
The over voltages will initially not be as great on a three phase circuit and the failures may be spread over a greater time.
By comparison, open neutral failures on a single phase circuit typically progress much more rapidly.
Bill
--------------------
"Why not the best?"
Jimmy Carter
EVERYTHING YOU WANTED TO KNOW ABOUT OPEN NEUTRALS.
The symptoms are fairly straightforward dik.
A combination of under-voltage and over-voltage from lines to neutral.
With balanced loads there may not be any indication of an open neutral.
A failing connection may introduce a resistance in the neutral circuit, further confusing things.
There are some tests that look good on paper or as sound bites that are difficult to perform and less than perfect under real world conditions.
Measure the neutral resistance? Easy to say but often difficult in the real world.
The neutral circuit includes everything from the transformer to the final panel, or to the load in the case of a three wire circuit such as is common in many kitchen receptacle circuits in North America.
As devastating as they may be, open neutrals are so rare that regular testing is not normal.
A check of the neutral resistance as part of the commissioning process may be required, but this will not predict problems years in the future.
Normally, an open neutral is detected or suspected by the symptoms.
Then a series of voltage checks and physical inspection is used to locate the problem.
eg: The voltages are normal at panel "A" but unbalanced at sub panel "B". Look for a bad connection between "A" and "B".
History is also important. The first time there is an issue with an open neutral there may be some time lost before the cause is identified and located.
The second time that similar symptoms arise, there should be an immediate response and an aggressive effort to locate and rectify the problem. What will an open or high resistance neutral look like in your home?
There is a difference.
The overwhelming number of open neutrals that I have encountered have been due to human error. As in the village idiot trying to be an electrician.
As a natural occurrence a high resistance connection is more likely.
This is often due to corrosion or heat cycling at a connection.
If you refer back to the sketch that Keith posted on 26 July, insert a resistance where an open neutral is shown.
Now with light unbalances there may be small change in voltage balance.
Consider a typical home in the morning:
A couple of lights, clocks and possibly a radio connected. A fairly low current through the neutral resistance and a fairly low voltage shift.
Now you plug in the toaster. Now we have a larger unbalanced current and a greater voltage shift. Along with the toast you want some coffee and the coffee maker happens to be on the same line. The radio happens to be on the other line and starts to release the magic smoke.
You call an electrician. You forget to tell him about the toast and coffee. (As a non-technical home owner you don't realise that it is important.)
The electrician checks the voltages and finds them to be reasonably close.
This may be the first time that he has ever encountered an open neutral. It may take him some time to locate the problem when the symptoms are not showing.
The second time this happens both the electrician and the home owner should immediately say;
"Looks like another open neutral!"
The first step in a successful CYA cover-up is is to set the terms of reference of the enquiry to exclude anything that will show your liability.
Bill
--------------------
"Why not the best?"
Jimmy Carter
The Equality and Human Rights Commission (EHRC) told the Observer it would look at whether the authorities failed in their duty to protect life.
This aspect, it said, was "currently overlooked".
Meanwhile, the leader of the council that owns the tower told the Sunday Times she would not attend a memorial service, after a request from families.
Elizabeth Campbell, who took over at Royal Borough of Kensington and Chelsea (RBKC) in the wake of the blaze, said the memorial service on Thursday marking six months since the disaster was not "about me".
The government appointed a retired judge to lead an inquiry into the 14 June blaze, which killed 71 people.
The EHRC's work will focus on whether the government and RBKC fell short in their duty to protect life, prevent inhuman treatment and provide safe housing.
London police are considering a variety of criminal charges related to the June fire at Grenfell Tower that left 71 people dead.
Police told an inquiry Monday that the possible charges include misconduct in public office, manslaughter, corporate manslaughter and breaches of fire safety regulation.
No one has yet been charged.
Jeremy Johnson, lawyer representing the police at the inquiry, said the scope of the investigation was "unprecedented" in a case that did not involve an extremist attack.
He said police are studying 31 million documents and 2,500 exhibits.
Johnson spoke at a hearing spelling out how a detailed inquiry into the disaster will be carried out.
Officials say the goal is to make sure there is never a repeat of the catastrophe.
where the likely areas of coverage for the report are detailed.
It doesn't look as limited in scope as some had portrayed it to be; I hope the judge has the the strength of character to pursue the investigation fully even though it will almost certainly cast a very unfavourable light upon parts of the UK's regulatory framework and upon both local and national government.
