Three wires come to the house from a pole in the garden,
they are 240v.
they have black plastic looking insulation on 2 of the three (I
presume the other unsheathed is earth?).
The wires are at an acute angle to the wall in question.

I need to get to the chimney stack with (ideally) a tower scaffold
which would come close to the wires as it ascends past them.

How close is sensible? how to analyse/rationalise risks?


or
Can I build a scaff tower slightly offset from the line of the stack
(i.e. a bit further away from the wires) and then *somehow* arrange
some safe scaffolding around the stack itself?

thanks for any (constructive;)) thoughts

Cheers
Jim K

On 02/08/10 16:10, Jim K wrote:
Three wires come to the house from a pole in the garden,
they are 240v.
they have black plastic looking insulation on 2 of the three (I
presume the other unsheathed is earth?).
The wires are at an acute angle to the wall in question.

I need to get to the chimney stack with (ideally) a tower scaffold
which would come close to the wires as it ascends past them.

How close is sensible? how to analyse/rationalise risks?


or
Can I build a scaff tower slightly offset from the line of the stack
(i.e. a bit further away from the wires) and then *somehow* arrange
some safe scaffolding around the stack itself?

thanks for any (constructive;)) thoughts

The power company came out and put yellow sheathing round our power
cables for free when we had a bunch of deliveries last year via HIAB lorry.

On Mon, 02 Aug 2010 16:23:00 +0100, Jim wrote:

The power company came out and put yellow sheathing round our power
cables for free ...

Yep, scaffold company arranged that for us before the scaffolding
went up last week.

--
Cheers
Dave.

Jim K wrote:
Three wires come to the house from a pole in the garden,
they are 240v.
they have black plastic looking insulation on 2 of the three (I
presume the other unsheathed is earth?).
The wires are at an acute angle to the wall in question.

I need to get to the chimney stack with (ideally) a tower scaffold
which would come close to the wires as it ascends past them.

How close is sensible? how to analyse/rationalise risks?


or
Can I build a scaff tower slightly offset from the line of the stack
(i.e. a bit further away from the wires) and then *somehow* arrange
some safe scaffolding around the stack itself?

thanks for any (constructive;)) thoughts

Cheers
Jim K
If it is going to be just you going up the scaffold then common sense is
the rule. If you want - slip some pipe insulation over the cables but
not really necessary tbh.

If you are asking others working for you to go up there then
commercially erected scaffolding will (should!) cover you from a risk
point of view as they will have an accepted procedure compliant with
their insurance.

Bob

On Aug 2, 4:10*pm, Jim K wrote:
Three wires... they are 240v.
I need to get to the chimney stack with (ideally) a tower scaffold

Also, consider asking for a glass fibre scaffold tower.
They exist and in some cases are no more expensive (because they are
not hired out often).

In article ,
Jim K writes:
Three wires come to the house from a pole in the garden,
they are 240v.
they have black plastic looking insulation on 2 of the three (I
presume the other unsheathed is earth?).
The wires are at an acute angle to the wall in question.

I need to get to the chimney stack with (ideally) a tower scaffold
which would come close to the wires as it ascends past them.

How close is sensible? how to analyse/rationalise risks?


or
Can I build a scaff tower slightly offset from the line of the stack
(i.e. a bit further away from the wires) and then *somehow* arrange
some safe scaffolding around the stack itself?

thanks for any (constructive;)) thoughts

As others have said, get them sleeved for free by the power company.

Back when ogrish.com still existed, many pictures of smoldering
bodies as a result of contacting overhead lines with scaffolding
(although mostly higher than mains voltage).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 2 Aug, 16:23, Jim wrote:
On 02/08/10 16:10, Jim K wrote:



Three wires come to the house from a pole in the garden,
they are 240v.
they have black plastic looking insulation on 2 of the three (I
presume the other unsheathed is earth?).
The wires are at an acute angle to the wall in question.

I need to get to the chimney stack with (ideally) a tower scaffold
which would come close to the wires as it ascends past them.

How close is sensible? how to analyse/rationalise risks?

or
Can I build a scaff tower slightly offset from the line of the stack
(i.e. a bit further away from the wires) and then *somehow* arrange
some safe scaffolding around the stack itself?

thanks for any (constructive;)) thoughts

The power company came out and put yellow sheathing round our power
cables for free when we had a bunch of deliveries last year via HIAB lorry.

do they come out and remove it too?
were your wires "bare" before they did that?
what did they do where the wires met the building? - we have a "3 pole
bracket" for want of a better descrip....

Did your scaff rub touch the wires? go near them (how near)?, straddle
them?, something else?

Cheers
Jim K

On 2 Aug, 18:23, "js.b1" wrote:

Also, consider asking for a glass fibre scaffold tower.
They exist and in some cases are no more expensive (because they are
not hired out often).

In some places they're the only sort you can get - Scousers will nick
the aluminium ones overnight!

On Mon, 2 Aug 2010 12:34:28 -0700 (PDT), Jim K wrote:

do they come out and remove it too?

I hope so...

were your wires "bare" before they did that?

We only have two incoming wires, the "live" is insulated, but it's
not very thick, really only to prevent casual contact rather than any
form of robust protection. The "neutral/earth" is bare copper.

what did they do where the wires met the building?

The sleeves cover up to the insulator a bit of tape was wrapped
around the join between the cable running into the house and the
overhead line.

Did your scaff rub touch the wires? go near them (how near)?, straddle
them?, something else?

The scaffold (as installed) is clear of the cables. The cables do
cross a riser at about 4', clearing of the top of the guard rail by
about a foot. The sleeve being quite large 30 mm dia with a 20 mm
yellow flash below makes them far more obvious when moving about on
the riser.

--
Cheers
Dave.

On 02/08/10 20:34, Jim K wrote:
The power company came out and put yellow sheathing round our power
cables for free when we had a bunch of deliveries last year via HIAB lorry.

do they come out and remove it too?
were your wires "bare" before they did that?
what did they do where the wires met the building? - we have a "3 pole
bracket" for want of a better descrip....

Did your scaff rub touch the wires? go near them (how near)?, straddle
them?, something else?

It was the wire going down the road which we were protecting from lorry
mounted cranes - the scaffolding associated with our extension didn't
come close to where the wires came into our house and as a matter of
fact we've now done the work to bring the wire into a meter cabinet via
an underground trench.

The sheathing hasn't actually been removed yet.

On Mon, 2 Aug 2010 18:39:54 +0000 (UTC), Andrew Gabriel wrote:

Back when ogrish.com still existed, many pictures of smoldering bodies
as a result of contacting overhead lines with scaffolding (although
mostly higher than mains voltage).

At this point in our supply the wired pole fuse is 200A. 48kW makes
for a at lot of energy to be dissipated before the fuse even thinks
about going pop...

Would the auto-recloser on the 11kV detect the "fault" on the 240v
side? After all there would be more power going than coming back as
some would be going via the real earth. All the same that
auto-recloser puts the power back on 3 times before locking out.

--
Cheers
Dave.

On 3 Aug, 10:11, "Dave Liquorice"
wrote:
On Mon, 2 Aug 2010 12:34:28 -0700 (PDT), Jim K wrote:
do they come out and remove it too?

I hope so...

were your wires "bare" before they did that?

We only have two incoming wires, the "live" is insulated, but it's
not very thick, really only to prevent casual contact rather than any
form of robust protection. The "neutral/earth" is bare copper.

what did they do where the wires met the building?

The sleeves cover up to the insulator a bit of tape was wrapped
around the join between the cable running into the house and the
overhead line.

Did your scaff rub touch the wires? go near them (how near)?, straddle
them?, something else?

The scaffold (as installed) is clear of the cables. The cables do
cross a riser at about 4', clearing of the top of the guard rail by
about a foot. The sleeve being quite large 30 mm dia with a 20 mm
yellow flash below makes them far more obvious when moving about on
the riser.

--
Cheers
Dave.

intellisting ta

how quick did they come out and do the sheathing from when you asked?
do they do it with long poles or something else "pedestrian based" ?
or something else?

Cheers again

Jim K

On Tue, 3 Aug 2010 04:13:52 -0700 (PDT), Jim K wrote:

how quick did they come out and do the sheathing from when you asked?

About a week but I didn't arrange it the scaff company did and I
think they have direct contact with the boys that do the work, rather
than going through "customer services".

do they do it with long poles or something else "pedestrian based" ?

Up a ladder against the wall where the cables are attached.

--
Cheers
Dave.

On 3 Aug, 17:53, "Dave Liquorice"
wrote:
On Tue, 3 Aug 2010 04:13:52 -0700 (PDT), Jim K wrote:
how quick did they come out and do the sheathing from when you asked?

About a week but I didn't arrange it the scaff company did and I
think they have direct contact with the boys that do the work, rather
than going through "customer services".

do they do it with long poles or something else "pedestrian based" ?

Up a ladder against the wall where the cables are attached.

--
Cheers
Dave.

many thanks Dave
CHeers
Jim K

On 3 Aug, 10:21, "Dave Liquorice"
wrote:
On Mon, 2 Aug 2010 18:39:54 +0000 (UTC), Andrew Gabriel wrote:
Back when ogrish.com still existed, many pictures of smoldering bodies
as a result of contacting overhead lines with scaffolding (although
mostly higher than mains voltage).

At this point in our supply the wired pole fuse is 200A. 48kW makes
for a at lot of energy to be dissipated before the fuse even thinks
about going pop...

HRC fuses generally have a 'fusing factor' of 1.5, meaning 300A (72 kW
@ 240v) will need to flow before it blows rapidly.

Would the auto-recloser on the 11kV detect the "fault" on the 240v
side? After all there would be more power going than coming back as
some would be going via the real earth. All the same that
auto-recloser puts the power back on 3 times before locking out.

--
Cheers
Dave.

It wouldn't detect an earth fault on the LV side, because the fault
current would return to the LV neutral point, same as load current,
unless possibly it was of very low impedance, amounting to a L-N short
close to the transformer.