Wednesday, 14 September 2016

Safe Withdrawal Rates - with respect to inflation ...

The subject of Safe Withdrawal Rates is cropping up again regularly on the blogs, so I thought I'd take a quick look at it myself.

The general acceptance criterion seems to be a drawdown rate at which an initial capital sum would last for 30 years without becoming depleted, after the withdrawn amount is increased annually in line with inflation.

Instead of trying to predict any particular safe withdrawal rate, I decided to take a slightly different approach and examine what the annual investment growth rate would need to be to sustain a 4% rate of withdrawal, and with reference to the assumed inflation rate.  4% is the oft-quoted safe withdrawal 'rule'.

So I set up a simple spreadsheet based on a £100k pot from which an inflation-adjusted amount is withdrawn each year, and then I played around with various input values.

Sunday, 11 September 2016

Sunday, 4 September 2016

Overhead Power Cable to the Greenhouse.....

I recently decided to remove the solar panels from the greenhouse roof.  After several years of daily charging & discharging, the deep-cycle batteries were almost completely shot and to replace all three batteries would have cost around £150.

However, I still like the greenhouse to be illuminated by the LED growlights in the evenings, so I priced up a few bits and pieces and reckoned I could fix up an armoured mains power cable from the house to the greenhouse for only around £60 in total.

Running a mains cable will also let me use my two heated propagators in the late winter, to get a headstart on the vegetable seed sowing.

If I ran the cable underground from the house it would need to cross the concrete driveway. This whole hardstanding area to the front and side of the house could probably do with being completely replaced, but since there's more than 150 square metres in total it's a very big ticket project and therefore it's not a high priority.  Still, there seemed little point in routing an underground cable across there if it's likely to need digging up in the future.

So I decided instead to route the cable overhead, a distance of around 11 metres from the front corner of the house to the entry point at the greenhouse.

The first job was to establish a few basic design parameters and buy the necessary equipment; a 25 m length of 3-core 2.5 square millimetre cable with galvanised steel wire armouring (SWA), a pair of guide tubes, U-bolts and wire rope clamps.

cable with outer sheath stripped and armoured wires cut back