Help with reading site plans for wiring regs

[John Lundrigan]

Hi All,
I am hoping to that someone might be able to point me in the direction of a suitable resource that will help me interpret the details of site electrical plan that will allow me to get the necessary details that I can use for cable calculations.

I came across this issue when I was asked for help in completing a C & G 2357 assignment. Whilst I'm OK with cable calculations per se, I've never had to do this from a site plan. It may be that the only way I can do this is by doing a C & G 2357 course, but I don't want to go that route.

What I need is perhaps just some tips or some publication that may enlighten me.

For example, I need the lengths of cables and I have assumed that I can measure these on the plan and use the plan scale to do this.

Thanks in advance

Jonel

 

[Andy78]

Yes measure the cable lengths from the plan and carry out calcs in accordance with the wiring regulations.

 

[John Lundrigan]

Thanks Andy

 

[westward10]

Do the plans show the vertical drops.

 

[Strima]

Do the plans show the vertical drops.

Often forgotten when designing from plans. Especially switch drops.

 

[Spoon]

Often forgotten when designing from plans. Especially switch drops.

That's silly of them...

 

[John Lundrigan]

Hi Westward,
The only vertical information I have is the heights of the structure.

 

[Andy78]

Hi Westward,
The only vertical information I have is the heights of the structure.

As long as you remember to include for the vertical bits you won't get lost.

 

[Deleted member 26818]

Most plans don’t correspond with realit, so relying on them for cable lengths is always just a guesstimate.

 

[John Lundrigan]

Yes, I understand that, but the question is assessing the ability to make that guesstimate so I wanted to know if that was the correct process.

 

[Baker1988]

What is the unit of the 2357 this plan is off? As from what i remember from my 2357 is the design units was basically a blank plan of the building and stated dimensions like height and lengh of the building and also stated what the supply characteristics was and where it was located and you basically design the rest from containment to cables and so on so yes you basically get a scale ruler (there should be a scale on the plan somewhere) then you measure it all and design your cables from there including the containment so dont forget the grouping factors and stuff in if in trunking and also as stated above dont forget the drops to sockets and switches and also the drops down to the distribution board.
Have a go at it and post up a pic of what you have chose and your calculations and we can advise if you are right or wrong.

 

[John Lundrigan]

Thanks Baker 1988, that was a really helpful response.

 

[davesparks]

What is the unit of the 2357 this plan is off? .

According to the OP it’s not part of the 2357, so presumably this is a real job.

 

[telectrix]

measure up from plan add 50%to all cable runs. then do the calcs.