Member postings for Robert Atkinson 2

You can buy commercial removers, google bathtub rust stain remover. Most seem to be North American origin. One I checked in a hardware store there had hydrofluoric acid as the active ingredient. It was fairly dilute but HF is nasty stuff.
A home remedy is a paste of sodium bicarbonate and water but I've no idea how effective it is an you would have to empty the trap if used on a toilet.

Robert G8RPI.

That process is not anodising, its a chromate conversion coating. One advantage is its conductive, disadvantage is the traditional process uses hexavalent chromium which is toxic and banned in most applications in europe and other counntries.

Robert G8RPI.

Seeing as the face of the boss on the existing backplate is not machined you have to use the rim of your adaptor as the registration surface.

Even if both surfaces were machined I'd still make the central recess deeper to give clearance. Less chance of having a bit of swarf or dirt trapped and causing misalignment. The rim is the larger diameter so will be the most accurate register.

Robert G8RPI.

The modern product would be glass tape with thermosetting adhesive. A good example is 3M's Scotch 69

https://uk.rs-online.com/web/p/cloth-tapes/8855268/ or 12mm https://uk.rs-online.com/web/p/cloth-tapes/8855255/

This can be used dry or varnished. Cotton is no longer acceptable due to flammability issues.

Robert G8RPI.

To add to Dave and Phil's comments on plug fuses, the plug fuse is there to protect the cable between the pulug and appliance. The fuse rating is based on the cable size. Obviously ther is releationship to th load because the cable must also be large enough for the load.
The letter rating of modern MCBs is mainly related to the time-current relationship and the higher ratings apply to the fast trip time (short term overload) of the MCB, the long term overload ratinging is the same. For examble a B or C rated MCB may be needed to stop start-up tripping with motors and VFDs.
I think the French ban ring mains because they are English
The ring main was developed during WWII and notably had a woman on the committtee. Saving copper was a goal but not the only one. TV crews hate radial circuits becuase if the turn one light off or on the voltage changes and this can affect the colour balnce of the other lights.
Leaving the earth bare in T&E is a good idea particuarly in conjuncton with a RCD. Any damage to or water leakage into the cable is likely to result in leakage to the ground conductor rather than external conductive parts so less chance of shock or fire.
I was taught electrical installation decades ago and would never have been allowed to get away with the workmanship prevelant today. Haven't done it as part of a job for a very long time but checked on what would be required to get "part P" competency last year. It mostly depends on the reporting body you join, one needed me totake a course with one of their approved training providers. The course was 3 days and mainly seemed to cover uing a Multi Function Tester and reading cable and MCB sizing tables. They did say if you have no prior experience you should tkae their 5 day initial course- nothing to part P in 8 days!

Robert G8RPI.

Even if we assume 0.1W (1mA is around 0.2W) and 3 chargers per home thats 7.2Wh per day times 27 million households is nearly 200 Megawatts hour per day! Many people have more than 3 chargers and then there are business users. It all adds up.

Robert G8RPI.

Edited By Robert Atkinson 2 on 22/04/2019 14:44:50

If the insulation in the charger breaks down making the output "live" then any current to ground over a few milliamps, includng through a person, will trip the earth leakage device. The earth leakage device does not even have an earth connection to it's circuits. It works by sensing any difference in current between live and neutral so will even protect against shocks between phases e.g. if you ran an extension lead from next door who are on a different phase.

Robert G8RPI.

The chargers should have fuses, but not the replacable type. The earth leakage and overcurrent breakers protect from leakage or shorts to ground and overloads, but the overload protection is for the cables only. It won't stop a device like a charger overheating as the circuit has to cope with wvething from a 10W charger to a 3000W heater. The current generation of overcurrent breakers can't detect arcing between live and neutral where hundreds of watts coulld be setting a fire. The latest designs can detec arcing and add extra protection but cost more. The earth leakage breaker protects against shocks and shorts or arcing to ground.

Robert G8RPI.

A charger that meets the safety requirements will have internal over current protection but it may not be a "fuse" in the traditional sense. Often they use a fusible resistor is used. This resembles a normal resistor but is designed to go open circuit before it goes up in smoke. The problem is the cheap chargers and clones, often from the far east. The cut costs and compromise safety. Running from a 3A fused extension is a good precaution and chargers should always be switched off or unplugged when not in use.

Robet G8RPI.

+1 for Morris lubricants. They even make steam oils.

Oops,
seems I found a "fake" KJD17B John is correct.

Robert G8RPI.

Considering that this "KJD17B"

https://www.ebay.co.uk/itm/KJD17B-250V-16A-Start-Stop-Switch-No-Volt-Release-Switch-With-Emergency-Stop/263083417338?

is a CK21 with a CE sticker over the CK21 mark (see last photo and compare to 4th photo of www.ebay.co.uk/itm/250V-16A-IP54-Start-Stop-Switch-No-Volt-Release-Switch-Emergency-Stop-for-CK21/202627005683? )

I'd say no there is no practical difference.

Robert G8RPI

Been there, done that - 21 years ago with a car!
https://www.reddit.com/r/pics/comments/uvtjg/shockwaves_visible_as_thrust_ssc_breaks_sound/ and http://www.flymicro.com/photolib/boom-boom.cfm

I know the two photographers, built the machmeter and was part of the team.

Robert G8RPI.

Also from the official MD application guide

The cut of bit refers to used or modified equipment and references guidance on the amount of refubishment or modification that requires compliance.

Pretty clear.

Robert G8RPI.

Russell you are correct in te the core directives are transcribed to countries law, but Andrew and Phil are most certainly NOT correct. If the requirements only applied to selling you could build or import items which were unsafe. See my post above for put into use/service requirements.

Robert G8RPI.

I concur with your brother, a fabric aircraft cover does not require CE marking and it would be illegal to put on on them. In fact they need no approval of any kind.

Put into use is in MD 1.7.1, 1.7.4, 4.1.3, and The Supply of Machinery (Safety) Regulations 2008v (UK implementation of directive section 3.9 says " A person who is not a responsible person shall not put machinery into service unless it satisfies the applicable essential health and safety requirements and is safe" i.e is CE compliant and section 7 says "
(1) No responsible person shall place machinery on the market or put it into service unless it is safe.
(2)Before machinery is placed on the market or put into service, the responsible person must— (a)ensure that the applicable essential health and safety requirements are satisfied in respect of it; (b)ensure that the technical file is compiled and made available in accordance with the requirements of Annex VII (Part 7 of Schedule 2), part A;

The other directives have similar provisions.

Robert G8RPI.

That is a useful link but must be read while remebering the authors are selling conformance assistance services so may have a bit of bias.

I think the problem they are refering to is insulation breakdown due to high back EMFs generated under low load starting. This is less of a problem with modern winding insulation materials.

Robert G8RPI.

I'd say a B for effort, but not compliant. The big problem is there appears to be on no-volt release (start/stop buttons) or emergency stop (or any other means of turning it on or off except at the socket or reaching under the table).

At very least put a switch on the table.

Robert G8RPI

You are being obtuse again I'm not sure what not being able to mae somone do somthing even when provided with the "tools" ha to do with my comment. From the rest of you post I'll guess you are saying that having a TCF does not stop the plane crash. This is true, but it means that there is something wrong with the requirements, not wht the manufactuer did. Unless they could prove the manufacturer knew there was a real risk and ignored it because they met the letter of the requlation (this would be wilfull negligence or similar legal term) the manufacturer is not liable.

I have been responsible for reviewing a suppliers qualification tests (RTCA DO-160, aviation not CE) and was accused of being very "black and white" about a minor exceednce (1 count of the measurement instrument over the prescribed limit liine). My response was that if it is on the limit line and the aircraft crashes I have no justification to make. One count over and I (and my employer) could be liable. True if one count over caused the crash then on the limit would almost certainly have the same effect. Problem is that even i the exceedance did not cause the crash scrutiny can be appilied to related areas. I bet there are a lot of people at Boeing right now havein deep thoughts about compliance. For things like this lawers are very black and white and if they are working for the insurance company you could be out of luck.

Robert G8RPI.