Member postings for Master of none

In discussions with Meggar, they recommended using the clamp meter around line and neutral together. A parallel path to earth through an extraneous conductive part (e.g. water pipe, gas pipe or structural steelwork) could reduce the current in the earthing conductor and give a misleading measurement of the difference between line and neutral currents. The clamp meter needs to cover the range 0-30mA.

Qualified is a term often used in manufacterer's instruction and is in my opinion, somewhat meanlingless regarding electricial installation work.

The Electricity at Work Regulations states that

"No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work". In my opinion, this applies more to installation and testing work which needs to be carried out safely.

BS7671 Requirements for Electrical Installations requires:

"Good workmanship by one or more skilled or instructed persons and proper materials shall be used in the erection of the electrical installation. The installation of electrical equipment shall take account of manufacturers' instructions."

Neither document stipulates the neeed to be qualified or the level of a qualification, except for a curious mention in BS 7671 of a "qualified electrian" in a sample notice regarding the temporary connection of a caravan to a plot supply point, It could be argued that a qualification may be evidence that an installer is "skilled" or "competent" but I have seen plenty of examples of individuals who have paper qualifications but whom could not be trusted to produce a safe installation unless thery are closely supervised. In addition, an electrician who is deemed competent to carry out domestic installations may not be competent to install systems in an industrial location.

Could I suggest that your refer to the "live" conductor as the "line". The neutral is connected to the supply transformer as well as being earthed, so technically, it is also a live conductor.

Probably true, but is smoking makes you more likely to suffer the effects of asbestos exposure

https://www.asbestos.com/asbestos/smoking/#:~:text=Smoking%20damages%20cilia%2C%20making%20it,scar%20tissue%20in%20your%20lungs

My concern with a latex screed is that it is not regarded as a finish. Similarly, cement and sharp sand is usually the bed for another finish but it could also be painted.

The traditional screed was was usually 50-75mm thiich bonded to the subfloor by coating with cement grout before laying the screed.. PVA on the subfloor is a better alternative. A good plasterer could achieve a flat and even finish but shrinkage of the screed may mean that it does not bond fully to the subfloor. However, the compressive strength of the screed should to be sufficient to support the machinery as the subfloor will provide the bending strength.

I agree with Clive on this one. As you have 40mm to accommodate, I would use some 18mm battens and 22mm green chipboard with glued joints. Some polystyrene insulation between the battens would make it more comfortable for standing. If you have high point loads for machinery, you could cut a core hole at each point and fill it with a hardwood plug bearing on the subfloor. That would eliminate the deflection of the chipboard floor. Some floor paint would add a finish.

I agree. Kitchen worktops are probably too thin to give you a relaible surface plate. I can measure slight curve in my granite worktop.

See Robin Renzetti's Youtube for lapping a granite surface plate.

I tried this test a while ago. Five pieces of identical plate suspended beneath the eaves of my garage for a period of months, From the left:

No treatment

Muck Off

3 in 1

WD40

Waxoil (best).

I use white spirit to remove it

I have had good results with Shell Ensis fluid or Waxoil from Halfords. Cutting tools well oilded in sealed plastic bags also seems to work. You may have difficultiy obtaining Ensis in small quantities

BS 7671 requires that the cables comply with relevant standards which could be British Standards or equvalent. SY cable does not have a particular standard. However it is widely used in industry for final connections to machines where inverters (VFDs) are used to control motors. The reason is that the braid on ST cable is earthed and helps to minimise the noise caused by the VFD which could affect other equipment.

SY is a useful cable but should not be considered as an armoured cable as the braid in not as tough as the steel wires in an SWA cable.

Yes, the cores are all black and are numbered but coloured sleeve could be used to identify the cores as Brown, Black and Grey.

Special brass cable glands are available terminating the cable but, in many cases, I have seen plastic stuffing glands used. It is important that the braid is earthed at the origin of the cable and that the terminations are not put under strain if the cable is pulled.

Edited By Richard Taylor 17 on 18/09/2022 21:13:10

I would fit a Wago on the cooked conductor once you have cut back the worst of the damaged insulation. Hopefully that is still within the terminal box of the motor. If you need to go back further, you would have to dismantle the motor far enought to expose the good part of the conductor, In that case, you bay be ettor off with a butt splice crimp to save space.

Could you use a Wago lever-type connector to extend the conductor? Easier to fit and you would not be trying to use a crimpt tool in a small space. As Wago connectors are constant pressure, they do not creep in a location where vibration can be a problem.

Do you know if the part was turned from a casting or round stock?. As I recall the workhead was not the easiest part to turn, particularly as the bore needs to be concentric with the pivot and the angled faces. Ideally the bore, pivot and angled face would have been turned in one setting of the part in on the lathe. Howerver the boss on the upper surface made it difficult to mount in the chuck of a small lathe.

In addition, there is little space between the boss and the bore to enable you to mount the piece between centres. A chunky purpose-made mandrel relieved on one side may be the solution to thet issue

One of the other challenges if you are starting from scratch is the undercut grooves. If you can salvage the part by fabricating a boss to fit, you could save some extra work, but it may be worth checking the concentricity before you start.

I hope this helps. I would be pleased to know how you get on.

One already has..

https://en.wikipedia.org/wiki/Thames_Gateway_Water_Treatment_Works

Conserving the planet is not just about principles and science but also about economics. A design solution for insulation in a building is affected by the prevailing interest rates more than just the energy to be saved vs the energy costs of the manufacture and installation of the materials. High interest rates wil discourage investment in energy saving measures as the future returns must be subject to greater discount. Hence the accountants can have significant influence in investment decisions unless regulation forces the pace.

Bulbs grow and lamps glow

Halogens lamps may be preferable to LEDs because of the lack of the stroboscopic effect.

I agree that Shell Ensis is very good for corrosion protection but it seems to be difficult to buy in small quantities. Waxoil is more readily available form retailers such as Halfords.

I was interested to validate some of the claims regarding the corrosion protection provided by various products. I cleaned and coated four samples of mild steel sheet with Muckoff, 3-in-1, WD40 and Waxoil respectively. I supended the samples together with an untreated control sample on PVC insulated wire under the eaves of my workshop where they were exposed to outside conditions but not direct rainfall or sunlight.   The samples after exposure - control, Muckoff, 3-in1, WD40 and Waxoil

The results suggest that most effective treatment was the Waxoil, so I use that product for long term protection of materials and surfaces which I would not normally touch.  It requires white spirit  to remove it.  For protection of tools, there is not a lot to choose between WD40 and 3-in-1.  Even the Waxoil treated sample showed some signs of corrosion, so it would benefit from an extra coat.

I have no commercial interest in any of these products.

Edited By Richard Taylor 17 on 21/07/2022 11:50:49

Beware of the dangers of fragments of optical fibre if using the material for anything other than commmunications. Fragments can stick to you skin and then be carried to your eyes or mouth. If your are working with optical fibre it is recommended that the work surface is dark in colout as the shards are more apparent.

I cannot agree that the olive needs to cut into the pipe. Once the copper pipe starts you yield under the force from the olive, you will never achieve a leak-free joint, however much you tighten it.

I certainly agree that the olive needs some lubrication. I alway use a smear of Boss White or similar. I know plumbers who swear by silicone sealant but that is not my preference.