How to Estimate your Modular Wiring materials in minutes, #1 - Commercial Office

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Why wait several days for a quote, when you can generate a bill of materials yourself in minutes, then issue it for simple comparative pricing?

Follow these simple steps and you will save days, freeing-up time to concentrate on the rest of your tender package. We are going to show you how to take the most common modular wiring project, the Commercial Office, and from your Lighting and FCU take-offs, produce a simple yet accurate estimate of materials.

MDBs/MDUs (Master Distribution Box/Unit)

Master Distribution Box (MDB)

1. Break MDBs down into No. of Ports required. Keep it simple. Assume separate Lighting and Power, and assume 6 Ports to be used throughout. (A different configuration may be pre-designed - even easier).

2. By DB, the quantity of circuits used = the number of ports required. Divide by 6 = MDBs. If no circuits, assume circa 12 luminaires per circuit. If you don't want to 'locate' your MDBs and scale-off the Home Runs, then simply assume an average length of around 18m. Check where the DBs are and scale-measure the furthest group of circuits to gain confidence.

3. Power MDBs, like the Lighting, circuits = ports, so divide the total by 6, (per DB). If the design is not circuited yet, allow 6No FCU per circuit, and again allow an average Home Run length of around 18m.

4. The only other implications are whether you want a pluggable DB Header, and what cable sizes are to be specified in the Home Run, but for simplicity, assume non-pluggable Home Runs c/w a 4mm bundle within.

Lighting Materials

• 5c 2.5mm² Extenders, 5 Pole Tee, 5c 1.5mm² Luminaire Leads, 2c 1mm Dali (to PIR)

1. Qty of luminaires + PIRs = Tees.

2. Qty of luminaires = 5c 1.5mm Connection Cable, all 2m for eg.

3. Qty of PIRs = 2c 1mm/Belden Connection Cable, all 2m for eg.

4. Qty Tees (No.1 above), = 5c 2.5mm Extenders. Allow an average length/lengths peaking at 3m. (Scale-measure typical distances if available).

5. Spec may help identify where, if any, armoured protection may be required, or assume LS0H throughout.

6. For LCM options, refer to earlier Blog.

Power Materials

• 3c 4mm² Extenders, Fused Spurs for FCUs

1. FCUs = Spurs = Extenders.

2. Again for speed, allow one simple average length of 8m.

That's it! Issue our estimate to the manufacturers and they will appreciate that it is simpler to quote a list of materials than it is to work through the tender enquiry themselves.

When left to the manufacturers to quote, in their defense, detail is often missed from the client, leaving them to make assumptions themselves. If you send your tender for a number of quotes, you will find you have a variety of interpretations returned.

For further help, advice or assistance, please contact us, visit our website, subscribe to Newsletters, and keep in touch for further articles, free advice and downloadable tools. We will create further articles in this series, identifying how to apply take-offs across all the sectors. If you don't feel comfortable doing these processes, please engage with us and we'll create the materials list required for any project.