PowerSwitch

NOT MINE.
I will be dong the electrical installation for a large domestic nuclear bunker, for obvious reasons the location and some other details will not be revealed.

Unusually this bunker is on two floors. The upper floor of the bunker has level access from the ground floor of the house and has only moderate blast and radiation protection. This area is more of a "panic room" in case of armed attack or civil disorder than a true nuclear bunker. It has reinforced walls and door, intended to withstand sustained attack with automatic weapons and builders tools, and to give some protection against light military weapons such as grenades or demolition charges.

It is equipped with backup power, basic food and water stocks, defensive equipment, communications equipment, and first aid supplies. CCTV is installed to monitor both the rest of the house, and the outdoors.

One small corner is heavily fortified and blast resistant, this gives access to the main shelter in the basement. Access via a flight of stairs and a manually powered "goods only" lift with a capacity of 250 kilos. Although not intended to carry persons it could certainly be so used in an emergency for anyone not able to use the stairs.

From a small lobby at basement level, the main bunker is reached via a second secure and blast resistant door.

I am only involved in the electrical aspects of this bunker, design and construction is already complete. Fitting out in hand. It is larger and better equipped than some houses !

Must be fascinating to get involved with such projects.

Have you read 'Bunker: Building for the End Times' by Bradley Garrett? He travels all over the world meeting people who are building bunkers.

Can you say anything about the owners? What's their world view? Why build it? Is it secret (how is that even maintained with contractors)?

The owner is a retired military person. Sensible IMHO.
Yes it is meant to be secret. Only contractors approved by HM forces did the building and structural work, and believe it to be covered by the official secrets act.

Fitting out and minor works only by persons known personally to be reliable. Stocking up with "ordinary" goods done gradually. Anything "out of the ordinary, or liable to attract attention" was delivered to an assumed name in a rented office.

Can you elaborate a bit more on the electrical system. Eg voltages, storage if any and any counter EMP precautions taken.

In any case please keep up these “doom porn” posts as I love them.

There are three electrical systems. The first is standard mains without any special features or protection, useful whilst times are normal but most unlikely to be available during any serious emergency. Supplies standard fluorescent lighting, battery chargers, and a large fridge, water heater, small electric cooker.

Also an extensive 12 volt system.

Two battery banks each 10 cell, 12 volt alkaline. Each bank is of about 2,000 ampere hours. One battery in use and one in reserve.
Lighting load with normal use in battery mode is about 15 amps daytime/2 amps nightime.
Lighting load with extreme economy is about 2 amps daytime/zero nightime.

Electric air blower uses 10/11 amps, continually unless hand cranked. Air blowers are triplicated but only one used at any one time.

Daily amp hour use estimated as 260 for ventilation and 200 for lighting and about 40 for incidentals. Say about 500 amp hours a day. 4 days runtime from the first battery, and two weeks from the second battery since use of the reserve battery is a warning to reduce lighting and to hand crank the blower.

Two small diesel generators are installed. 12 volt electric start with cranking handle in reserve. Each is about 6 kw. Supplies a 100 amp battery charger for each of the two batteries, engine room ventilation, water supply pump, TV, computer, and either a washing machine, OR the water heater, OR a small cooker, OR a vacuum cleaner.

Water is from a deep well within the shelter. Electric pump from generator or hand pump, into a 250 liter cistern. Hot water cylinder in addition.
Cold water supplies kitchen sink, washing machine, toilet flush. Hot water supplies shower and kitchen sink. 12 volt water pump for shower, remainder gravity supply.
Toilet and other waste gravity to soak away.

The intended number of residents could survive at least a year in modest discomfort. The limiting factors being food stocks, diesel fuel, or the breakdown of anything vital. Everything important is duplicated, at least.

EMP precaution WRT the electrical system are fairly limited, with the fact of being below below ground forming the main protection.

The electrical installation in the ground level panic room is basic without any special EMP precautions. It is regarded as expendable in an EMP event.
Two 13 amp sockets and a couple of lights from a dedicated circuit supplied by public mains. Self contained emergency light.
Plan B is a single deep cycle battery for minimal lighting and for communication equipment.
Plan C is candles and glow sticks.

In the main bunker, the incoming mains supply is fitted with an industrial quality surge protection device. Any gross over voltage should result in blowing of the fuses. As a departure from the regulations, there is a fuse in the neutral as well as in the live.

The 12 volt wiring is all in steel conduit, well earthed, not for electrical safety but in the hope of minimising EMP damage.
The negative side of each battery is earthed to the steel reinforcement of the structure.
All fixed 12 volt lights are so wired that when turned "off" they are short circuited rather than simply disconnected. All 12 volts lights use readily replaceable 12 volt lamps. No built in driver circuits or ballasts in the fittings.
Plan B is a good stock of spare lamps in a metal cupboard.
Plan C is a good stock of low powered incandescent lamps.
Plan D is lanterns and flashlights that use dry cells, proper bunker lights that give 100+ hours service on one set of batteries. Spare batteries and bulbs stocked.
Plan E is candles.

All portable 12 volt equipment is to be unplugged when not in use, as a third line of defence.

The duplicated diesel generators are of a simple and older type without any electronic controls. Output circuits in earthed steel conduit, with fuses. no MCBs or RCDs allowed.
The generators are earthed to building structure.
Fuel filters and engine air filters are stocked.
Engine room vent fans are duplicated FROM EACH ENGINE so FOUR fans in total. Simple direct drive induction motors, NO ELECTRONICS ALLOWED.
The fan motors are short circuited when not in use.
Generator starter motors are 12 volt, one connected to each of the two main battery banks. No changeover except by manually altering the wiring.
Plan B if engine wont start from battery is to try the other one.
Plan C is to use the cranking handle. Manual decompressors on engine to ease this.
Plan D is to try again with aerosol can of easy start.
Plan E is use of cartridge start system, uses an explosive device.

Many thanks for that insight. Sounds like an interesting project.

I would have never thought to have a double-pole-double-throw switch (I presume) short circuiting in the off position.

Really interesting technical challenge, I wonder what the likelihood of it actually being used/necessary is? What's the chance of a nuclear detonation within 50 miles of this chaps house within the next 20 years? 10%? 1%? 0.1%? It seems like a lot of time, effort, space, expense etc to provide a chance (he might be away from home when the bomb drops!) to protect against a small risk. I wonder how he approaches other risks? Does he have a exemplary diet? No alcohol, no smoking etc? Does he pay thousands of pounds for private medical screening each yet? Does he drive etc... If the chap's going die in his sixties rather than his eighties, it's mostly likely to be cancer associated to lifestyle choices, in which case aggressive screening is likely to pick it up earlier and result in a much high survival chance for example.

Regarding risk, how rational is building a bunker compared to all the other things we can do to reduce the risk of untimely death?

Or maybe building a freeking bunker is just a lot of fun!?

Generally fairly good diet.
Non smoker.
Drinks in moderation.
Private healthcare, inc six monthly check ups.
Drives, carefully, prefers train for long trips.

They consider that a nuclear attack within the rest of their life is likely, from terrorists or rogue states.
A bunker still gives some protection even if one is away from home during the attack, provided that one can get home and in shelter before the fallout descends.

The bunker also gives protection against civil disorder/rioting, pandemic/plague, or chemical warfare. The supplies stored in the bunker could be very useful in case of serious food or fuel shortages.

They consider not just their own welfare, but that of younger family members.

"from terrorists or rogue states"
Thats interesting, I rate that likelihood far lower than Russia or China.

Good point about more general use though. One risk I'm expected out west here in the next 30 yrs is serious wind storm, extra tropical cyclones... Wouldn't exactly build a bunker, but a root cellar dug into a hillside could be a good place to hunker down as 120mph winds do their worst.

clv101 wrote: ↑11 Jan 2022, 17:42One risk I'm expected out west here in the next 30 yrs is serious wind storm, extra tropical cyclones... Wouldn't exactly build a bunker, but a root cellar dug into a hillside could be a good place to hunker down as 120mph winds do their worst.

Have you thought about protecting your house / garden with some pollarded trees ? I had some around my woodlands back in Kent and they provided quite a good windbreak.

Yes! Poplar already in position, only 3-4m high so far.

clv101 wrote: ↑11 Jan 2022, 15:59 Or maybe building a freeking bunker is just a lot of fun!?

This Tourettes sufferer clear thinks so.

I would build one myself in Australia if I had the money and the space and I would use it as the ultimate passiv haus.

I cannot help but feel that despite the herculean attention to detail in this project
there may well emerge several unanticipated flaws in the execution of the concept.
Personally I would not want to work for such a paranoid control freak. Good luck.

It probably needs testing out for three or four weeks before it is actually needed. I would hate to lock myself in there when it was absolutely needed and then find that I had forgotten something essential or left it outside!