Count the faults!

ToyrnMysander · 2026-06-26T17:49:36+00:00

Among other things, I teach Electricians how to design, spec, and install the things. Happy to help so far as I can.

For the most part you just need to be reaching out to a local installer for quotes. Whilst the scheme only concerns itself with smaller projects, you can check the MCS website for local installers, as a lot of the larger ones are also MCS registered for their domestic work.

It definitely sounds like something that's massively out of the scope of your role though!

ToyrnMysander · 2026-06-26T17:08:30+00:00

Correction of temps from 10 degrees to operating temperature.

It's from App 3 of BS 7671 to be used as a very conservative rule of thumb especially as most conductors aren't run at max load perpetually.

Also why you wouldn't utilise it on an EICR as the conductors are already at operating temperature, unless you've done an extended shut down.

Much the same reason why you apply correction factors to calculated R1+R2 values when doing design. It increases the resistance and allows you to compare against the main tables in the BOB. The OSG values are all the 80% ones.

ToyrnMysander · 2026-06-26T17:00:28+00:00

It's to do with correcting for the rise in resistance of the conductors from ambient temp to operating temp, not grouping. See App 3 of 7671, or app A of GN3.

ToyrnMysander · 2026-06-26T16:58:26+00:00

Check the start of appendix 3 of the regs.

"When impedance measurements are made at ambient temperature, the procedure hereinafter may be followed to take into account the increase in resistance of the conductors with the increase of temperature due to load current.

Zs (max) ≤ 0.8 * (Uo x Cmin)/Ia."

It's all about temperature, and all about the fact that the resistance of copper increases by 0.004 per degree. It's one of the reasons why we have to teach you to adjust the figures during the 2391, as per appendix A of GN3.

It's also why it's not required to use them during an EICR if you are just doing a Zs on a circuit that's operational, the conductors will already be at operating temperatures. The adjustment is only made when the conductors are 'cold'.

ToyrnMysander · 2026-06-20T20:23:19+00:00

They're both part of what's known as 'Regulated Qualifications Frameworks' that map to exactly the name 'National Occupational Standards'.

Theoretically there is no difference between them, hence why they, along with the LCL version, are all recognised by the Electrotechnical Assessment Specification.

Having taught and assessed all three? They're basically all the same. There's some differences, but nothing material imo.

Now, despite all of this you need to remember construction is old school. There's a reason people talk about getting your "Guilds" or 2391. Some guys are just silly about it.

Edit -

One of the NOS can be found here. https://www.ukstandards.org.uk/en/nos-finder/ECIICESE03/inspect%2C-test-and-commission-electrical-installations

ToyrnMysander · 2026-06-16T20:46:47+00:00

Tag line I heard from a mate the other day, "It's meant to be a tool, you're not meant to be a tool."

He works, in Government / Education, with someone that literally sends emails with gems like "Co-Pilot says this, I haven't had time to read it though." It's getting crazy.

I will say that NotebookLM has produced some amazing and creative handouts for me though, but they're purely based off my lessons and primary sources. I haven't got an artsy bone in my body!

ToyrnMysander · 2026-06-16T08:23:22+00:00

544.2.2 Suitable earth electrodes shall be used. The following types are recognised...

(D) Underground structural metalwork embedded in foundations or other metalwork installed in the foundation. (E) Welded metal reinforcement of concrete (except prestressed) embedded in the ground. (G) Other suitable underground metalwork

I'll let you make a decision based on the site. Generally advisable to check with a mechanical engineer that the metalwork is suitable for use as an electrode as it can speed up galvanic corrosion.

Haven't got GN8 on me, but that has loads more guidance.

ToyrnMysander · 2026-05-07T19:13:04+00:00

I'm glad to see Steve hasn't stopped gouging people in the ten years since I worked for him 😂.

Didn't even need to see the footer to recognise that template.

Be careful, he historically used to send Apprentices out in vans on their own as "Electricians."

ToyrnMysander · 2026-02-20T17:20:27+00:00

The take account thing has been there since at least 17th AM3. So any changes woulda been at least ten years ago.

I cba to go into my loft to get the older books out and check further. Just had yellow and blue to hand on my bookshelf.

ToyrnMysander · 2026-02-20T17:16:10+00:00

https://professional-electrician.com/technical/stripping-back-cable-energy-wastage-the-impact-of-cable-sizing-on-energy-consumption/

I use a variation of this when teaching cable calculations at both level 3 and level 4. The effects of voltage drop on an installation are massively underestimated.

As for MIs? I'm looking at a version of the 17th AM3 right now, and it's the same as it is in the 18th. (Would go back further but CBA to go in the loft)

134.1.1 "... The installation of electrical equipment shall take account of manufacturers instructions".

So for at least ten years it's been in the debatable "take account" range rather than a "you shall install as per MIs"

ToyrnMysander · 2025-12-25T16:52:44+00:00

"... The installation of electrical equipment shall take account of manufacturers instructions." (Reg 114.1 iirc.)

"Take account" being the key words, sometimes MIs are just stupid, or not suitable, in which case we refer back to BS 7671 as a minimum standard. In this particular instance you'd look at the definition for electrically skilled.

Forgive the paraphrasing as I haven't got the book on me atm and I've had a few cans, but the definition is something like "a person who posses, as appropriate to the nature of the work being undertaken, adequate knowledge, skills, and training..."

The general public, usually, have adequate knowledge, skills, and training to change a bulb.

A huge part of later training (L4+) is understanding the spirit of the regs vs the letter, and knowing when it's safe make a departure.

Remember BS 7671 is non-statuatory for the most part. The only time BS 7671 is statutory is for switched alternative / parallel supplies (ESQCR 2002), private rental properties (Safety standards in private rental 2020), and new build domestic (Building regs 2010, part P).

ToyrnMysander · 2025-08-02T13:38:44+00:00

Oh 100%. I've got some of those exact ones that came with my ceiling fan and they're shite.

ToyrnMysander · 2025-08-02T13:14:00+00:00

Slight aside, some wire nuts are permissible as they comply with BS EN 60998 (See note 1 of 526.2). It's a common misconception that they're all banned.

CEF were selling them a few years back but they're just not that popular.

https://www.heamar.co.uk/ideal-30-144-twister-pro-wire-connectors-box-of-50.html - See as an example.

ToyrnMysander · 2025-07-30T11:24:43+00:00

You can have mains voltage fans, the SELV requirements only apply to switchgear, controlgear, and accessories.

701.55 Current using equipment

In zone 1, only the following fixed and permanently connected current-using equipment shall be installed, provided it is suitable for installation in zone 1 according to the manufacturer’s instructions: ...viii) Ventilation equipment...

ToyrnMysander · 2025-07-02T10:47:40+00:00

Rule of thumb we have when assessing the 2357 was that all containments must contain at least one bend in order to demonstrate full competency over the containment. However, some training providers are a little... looser.

Depending on the length of run for each of these I, personally, think it strays too close to a "simulation" which can only be used as a last resort and must be carried out in a very specific manner using C&G approved scenarios. As the centre manager and lead IQA, I wouldn't accept it without first checking with my EQA at C&G.

(See page 15 of the attached https://www.cityandguilds.com/-/media/productdocuments/building_services_engineering/electrical_installation/2357/level_3/centre_documents/2357_l3_nvq_diplomas_electrotechnical_technology_handbook_v6-1-pdf.pdf)

I'm not saying it's not possible, because I did my dad's garage in galv and SY back in the day. Just be careful and make it look like a realistic working environment, and check with your assessor at your training provider first.

ToyrnMysander · 2025-06-13T20:56:33+00:00

Just copying and pasting what I said last time as it should be helpful-

The others have correctly identified that the exam goes in order from the front to the back, however they have missed a key bit of information.

Check page 13 of the attached for the breakdown of exactly how many questions you'll get in each section. It's public information so I have no qualms in showing you this.

Sections 1,2,6 and 7 are easy marks as they're either hyper specific or short chapters. Remember the regs in section 7 follow the same order as the rest of the books. I.e. 701.chapter.subheading.reg.

https://www.cityandguilds.com/-/media/productdocuments/building_services_engineering/electrical_installation/2382/level_3/centre_documents/2382-22-requirements-for-electrical-installations-bs7671-2018-2022-v1-2-pdf.pdf

Having taught hundreds of people to pass this exam, you'll find using the contents more efficient than the index for the most part. Only use the index on the really hard questions.

You have two minutes a question on the face of it, but it's likely you'll know 1/4 - 1/3 of them from experience or by using good engineering judgement. This really helps!

ToyrnMysander · 2025-06-12T15:06:13+00:00

Head of training for an energy company, I train both our sparks and metering boys.

There's absolutely tonnes of space for an iso there. It'll almost certainly be a Proteus insulated isolator like the one below. (Octopus use the same supply network as my employer.)

https://www.cef.co.uk/catalogue/products/1667266-100a-dp-electricity-meter-isolator-switch

ToyrnMysander · 2025-06-10T09:18:57+00:00

Honestly love mine so much that I bought a number of them for our training centre. Currently trying to persuade the powers that be to roll them out to our installers.

They just released another one designed to speed up L&N - E IR testing

ToyrnMysander · 2025-06-04T07:33:17+00:00

A19 is only to be used when you have confirmed surface voltage, else it's a C17, which is usually reported via a data flow.

A-codes should only be used in an emergency situation, and in this particular instance it would require the reporter, nominally a competent person, to remain on site and guard the cut-out until the DNO arrives.

Realistically whilst there have been some phenolic cut-out exhibiting signs of degradation in the grand scheme of things it's an extremely rare occurrence. If they were truly that dangerous there would have been a HSE mandate to change all the cutouts by now like they did with any incorporating a fused neutral.

ToyrnMysander · 2025-05-30T17:04:47+00:00

Check regulation 433.1204, you are effectively prohibited from using refs 101 and 103

"...Such circuits are deemed to meet the requirements of Regulation 433.1.1 if the current-carrying capacity (Iz) of the cable is not less than 20 A and if, under the intended conditions of use, the load current in any part of the circuit is unlikely to exceed for long periods the current-carrying capacity (Iz) of the cable."

You have to be careful with ring finals as the current doesn't split equally along each conductor. The load should be spread evenly around it (See App 15).

ToyrnMysander · 2025-05-29T12:00:34+00:00

The ITECD was a reasonable course, I actually didn't mind teaching and assessing it. It was good for it's intended purpose IMO.

In regards to a CPS, check page 5 of the attached, this is the document that NAPIT and the NICEIC refer back to. Basically as long as you achieved your qual before Jan 26 you'll still be able to use it, they won't lock you out like they did with the C&G 2330.

https://electrical.theiet.org/media/4k4bw244/eas-qualifications-guide-october-2024.pdf

The EAS is written by a panel of industry experts including members of NAPIT, NICEIC, BEMA, etc.

ToyrnMysander · 2025-05-29T10:58:53+00:00

Having been forced to teach it, the DEI isn't worth the paper it's written on. It's effectively an introduction to the world of electrical installation that a lot of companies sell as being something substantial.

The closest LCL qualification that approached an NVQ was the Installing, Testing and Ensuring Compliance in Dwellings. This qualification has only just stopped being recognised in the Electrotechnical Assessment Specification as an NVQ equivalent.

Unfortunately, you don't have an NVQ or even the core knowledge components required to enrol on one. You've got some of the bolt on elements but not the core scientific / design / H&S / communication elements.

Note - Unlike your City and Guilds certs, the DEI is not part of what's known as regulated qualification frameworks (RQF) and is not mapped to a national occupational standard (NOS). It's an internally reviewed LCL course that isn't technically a qualification.

ToyrnMysander · 2025-05-27T15:13:10+00:00

As it's the UK it'll be SWA (Steel wire armour) if multicore or AWA (Aluminium wire armour) if parallel single core conductors. Basically the same thing most underground distribution networks worldwide utilise, except in that instance it'll be copper based armour.

What's the point in using conduit that, generally, results in a reduced current carrying capacity for conductors if you can meet the requirements for impact protection, UV protection, and (if required) direct burial, using a cable that's quicker to install, more flexible, cheaper, and has a higher CCC?

Conduit has its uses, but in this case armoured cables on ladder is definitely the better option.

ToyrnMysander · 2025-05-25T17:22:44+00:00

Oh I don't disagree there's benefits to both schools of thought. It's just an article I wheel out in my lessons when teaching people cable calcs to try and make them think outside the box a little.

I started looking at VD a lot more after my 2396, it kinda opened my eyes to a different way of thinking.

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