Design Process                                                                                  Organising work

Type of cable (wiring system) 

Routing

Size of cable (calculations) 

                                                             Test 

                                                           Inspect

Paperwork

 

1. source information (constraints afffecting design)

2. position accessories etc. (usage of electricity)

3. allocate circuits and routes

4. decisde type of wiring systems and accessories

5. cable calculations (size of cable)

6. CPD and other devices.  

 

Also: Organising work.

 

Constraints

Legislation - statutory, non statutory

These fall into the two groups

 

_General

bs7671 - non

building regulations - b

 

_Specific

local authority (planning dept or building control

others: listed building status. 

 

Client requirements - brass or pvc or chrome affect

Sustainable design considerations -  means that it will last longer and eco_friendly. 

 

 

Client requirements

Detailed information from the client about the finished installation. KNows as the specification or 'spec'

it may include - aesthetic requirements

 

Drawings/plans and information from an architect

Drawings/plans and information from an electrical engineer

(both on clients behalf)

Other specific information. 

 

Sustainable design considerations

These are covered specifically in unit 201

benifits include:

Material and building cost reduction

smaller carbon footprint

better power consumption (efficiency/efficacy) 

reduced wastedisposal costs (weee/hazards waste regs) 

 

 

Location drawing (layout drawing)

 

As fitted or record drawings

these drawings are layout diagrams but show the actual 'as fitted' routed of cable and positions of equipment when it is not possible to follow the origional drawings. 

 

They form a permanent record of any deviations from architects origional specifications

 

included in the operational and maintenance (o&m) manual. 

 

 

 

What should you do before starting any job? 

risk assesment. 

A hazzard could or has harmed someone or killed them

a risk is how likely it is.

 

Hazards using sockets:

trailing leads - trip hazard

Stretched leads and plugs - fire hazard

Equipment blocking access - evacuation hazard. (also leads under rugs or carpet - fire hazard) 

 

Our main priority is safety. 

 

 

Switched and isolators

what about light switches, what is the main issue as well as safety. 

Finding them in the dark

They should be placed - next to doors - on the opening side. 

not obscured by furniture or fittings. 

at a reasonabke distance form other controls - fire alarm etc. 

 

Isolators must be easy and safe to access. 

 

Building regulations

Part M of the building regs tell us a minuim and maximum heights for switches and sockets. 

MAXIMUM 1200 MIN 450 ABOVE FFL (FINISHED FLOOR LEVEL) FOR SOCKETS, SWITCHES AND EVERYTHING ELSE. 2.a

Also building regs give a number of restrictions on positions of accessories in kitchens.

 

 

ccu's 

Part M of the building regs also mentions the position of CCU's. Although it does not specify exactly what we should so, it requires us to ensure they are readily accessible, especially for those with limited reach or mobility. 

 

Buried cables

Wiring system:

SWA, metal sheathed or in a conduit or duct. 

 

Depth:

min 500mm, preferable 600mm or deeper depending on the amount of disturbance of the ground likely ro occur. veg patches are often dug over to about 600mm

 

A warning tape should be laid above the cable at 150mm depth 

Cable runs should be marked on a drawing and kept with the completion certification for future reference. 

 

Choosing a route

Avoid sharp bends:

Swa and other cables have a min. bending radius

Avoid trees and planted areas:

Roots will make digging dificult and damage may kill plants. cultivated areas may be ploughed or dug over. 
Avoid buildings.

Footings and foundations often stick out boyond the edge of a building. 

It is difficult to dig along the edge of a structure

Avoid water!!

Lakes, ponds, rivers, streams

Avoid carparks, pavements, paths or tarmacked areas

Anywhere that will need resurfacing or makin good. 

 

 

A critical path network is a method of organising a work schedule for a number of different parts of a project. A number of subcontractors may be involved.

 

 

 

1st fix is where the walls are there but thats it, install cables, backboxed etc.

2nnd fix, making connections and putting faceplates.