sparks blog

SPARKS Blog: “But, I thought…”

no comments

Luke Wichard runs his My Trusted Electrician business around Greater London. In our latest blog, he reflects on making assumptions when he was training.

“Assumption is the mother of all mess-ups”.

Many moons ago, when I was going through my training, I heard this phrase a lot.

It was made quite clear to me that if and when I made a mistake, I mustn’t start my excuse with, “but, I thought”.

Looking back at it now, it was quite funny, but at the time it was often a huge embarrassment.

Sometimes I would automatically fight my corner with the phrase, “but, I thought” and in unison, the whole building site would shout back: “We don’t pay you to think. We pay you to know!”

If you treat every task you carry out with this perspective, you will rarely go wrong – and if you do, your argument won’t start with, “but I thought”.

Manufacturer’s instructions (MIs), most people don’t read them. It’s like a bloke admitting that he’s lost and asking for directions.

I’ll hold my hands up and admit that once upon a time I used to be exactly the same.

You can’t help but feel that if you’ve installed one electrical fixture/appliance then you’ve installed them all. But one stupid mistake later…

One sentence that started with, “but, I thought” and I automatically knew how daft I was for not reading the MI. Now I’m going to try and convince you to do the same.

Look at these photos below.

Manrose NVF100T
Manrose XF100T
Airflow Aura Eco Air













These are what I would consider as the most common brands of 230V timer fans.

I think everyone reading this blog will come across at least one of these extractor fans in their career.

Now ask yourself the question, “did I just plonk this on the 6 amp lighting circuit?”

Of course, you did. It’s a timer fan.

It wouldn’t work if it wasn’t on the lighting circuit.

Now I’m going to show you a paragraph from each of these extractor fans MIs.

Manrose NVF100T

Wiring of Standard Model – Diagram 2

This fan can be either operated from a suitable remote switch or a separate pullcord switch fitted to the ceiling of the room or can be connected to the light switch so that the fan will start when the light is switched on. The cable from the fan must be connected to a double pole fused spur having a contact separation of at least 3mm in all poles, it must be used and fitted with a 3 amp fuse, and should be sited outside any room containing a shower or fixed bath. The fan should not be accessible to a person using either the shower or the bath.

Manrose XF100T

(iii) A double pole fused spur having a contact separation of at least 3mm in all poles MUST be used and fitted with a 3 amp fuse, and must be sited outside any room containing a shower or fixed bath. The fan must not be accessible to a person using either the shower or bath. Fan to be fitted a minimum of 1.8 metres from floor. When fitting through an external wall, an external grille must be fitted at all times.

Airflow Aura Eco Air


The fan “Aura-eco” complies with the requirements according to the EU norms and directives. Level of protection from access to hazardous parts and waterproof is to IPX4 Connection of fans supplied with the electric cords to power supply as well as replacement of electric cord should be perfomed by a competent person (Part P) and in accordance with latest IEE wiring regulations. A 3 amp fused isolator should be fitted.

I can safely say that I don’t think I have EVER seen a 3 amp fused spur supplying an extractor fan whilst carrying out an Electrical Installation Condition Report on a domestic property. I have also never seen anyone else code an extractor fan in their observations. “But, I thought” springs to mind.

Along with extractor fans I’ve seen a variety of “but, I thoughts”.

Only equipment and arrangements specified in Hager’s technical documentation / catalogue shall be used.

I hope that this short blog may have opened your eyes to a few of the most common “But, I thoughts” in the domestic electrical industry.

By Luke Wichard





You can watch Luke’s YouTube channel here.

Previous SPARKS Blogs

Legal status and qualifications

Cable strapping and good workmanship

The Big Renewable Power Charge!

A guide to floodlights

Get smart – hire an apprentice

I’m Reg and I’m here to help you!

EV Charging and the 18th Edition

Other News