New dist. board

[Hawk]

Have a job coming up to supply a new distribution board. I am planning on running a 25mm 4 core swa and 16mm earth of a distance of 30mtrs from incoming supply to new board. The supply is 3 phase 100a tncs. I was thinking of coming out of the Henley blocks into a 100A Glasgow switched fuse and then the swa out of the switched fuse to a 80A 30mA 4pole rccb supplying the new board. Thoughts?

 

[Andy78]

Why an extra earth cable ?
Why an RCD and where exactly would it be positioned ?

Would be my immediate thoughts.

 

[Hawk]

I find it good practice to run a separate earth instead of using the swa. The rcd would be positioned below the board then tails out of it into the main switch. Reason for rcd is because it is a production area with access to outside where outdoor equipment may be used.

 

[Andy78]

I find it good practice to run a separate earth instead of using the swa. The rcd would be positioned below the board then tails out of it into the main switch. Reason for rcd is because it is a production area with access to outside where outdoor equipment may be used.

An extra earth is completely unnecesary, but whatever that's your choice.

One RCD covering the whole DB ? What size is the proposed DB and how many circuits and of what nature and use are the final circuits ? Do you think this will comply with the regs ?

 

[Pete999]

If the customer can stand the price install a 5 core SWA

 

[joehat]

Why 4 cores? Why not 2core?

 

[Pete999]

Why 4 cores? Why not 2core?

Three Phase supply

 

[Welchyboy1]

my standard set up would be, tails to switchfuse unit, swa to distribution board with main switch then rcbos for circuits that require it, or even better if containment allows, rcd socket outlets and no rcd potection at db at all

swa as cpc

if its to supply machines used in production, the last thing you need is that rcd mainswitch knocking out the whole area every time you get a small problem on one circuit

and why would you have it as a stand alone unit rather than as part of the db?

 

[Hawk]

I know what your saying, but as usual it's all down to cost. A 32A TP socket with rcd is around £360.

 

[Welchyboy1]

I know what your saying, but as usual it's all down to cost. A 32A TP socket with rcd is around £360.

Well if cost is the issue, then you need to give the customer the options(with the possible negaitive effects of cheaper choices)

and let him decide, and put it in his court when or if there are any issues later on

you dont want the phone calls in a months time that the machines are abit leaky and keep knocking out the whole board!

if you give him the choice at the start, problems afterwards are billable!

 

[Andy78]

I know what your saying, but as usual it's all down to cost. A 32A TP socket with rcd is around £360.

No it's not all down to cost it's about appropriate design and compliance with the regs.
Is that what price you have been quoted for a 32A RCD socket ? because if you look around they should easily be less than a hundred each.
RCBO is not an expensive solution is it ?

 

[Hawk]

True. I will give them the options and they can decide.

 

[Andy78]

True. I will give them the options and they can decide.

I'd give them the option of you designing the installation appropriately, safely, and compliantly, or you walking away.

 

[Hawk]

For some people it is about the price. How would what I described not be compliant with the regs?

 

[Andy78]

For some people it is about the price. How would what I described not be compliant with the regs?

Take a look at 314