High Resistance on Power Sockets

Foxana

Another 2 cents

As you may know, resistance depends on the copper temperature. So the readings you get under high load differ from those when nothing is plugged in. Also, when testing with Fluke, Megger, etc, they run tests under something around 400V to put cables at stress, so all bugs come out. So, you'll probably won't be able to get same readings with your meter.

We once had problems with continuity test (high impedance readings) when there was a bad contact between 2 ring legs in one of the sockets' connector. To find the fault, we had to undo half the sockets, but when cleaned, rubbed with sandpaper and intertwisted to make sure good contact, the readings came back to normal. So you might anticipate what you're up to

With regards to gas. Making a gas leak test on a meter is dead simple and the tool is cheap as chips. Most of the leaks on pipework/connections you can detect with a bit of Fairy dissolved in water (to see bubbling when leak occurs). At 20 mbars (normal domestic gas pressure) the leak has to really build up for a looooong time to make a big bang I am looking forward for Chinese manufactures to come up with cheap gas sniffer to make things even easier.

Owain_Moneysaver

Foxana wrote: »

With regards to gas. Making a gas leak test on a meter is dead simple and the tool is cheap as chips. Most of the leaks on pipework/connections you can detect with a bit of Fairy dissolved in water (to see bubbling when leak occurs).

Washing up liquid usually contains salt, and is corrosive. It is also insufficiently viscous to stay on the joint making it more likely it will run off and a leak will be missed. Proper leak detector spray should be used.

Foxana

Owain_Moneysaver wrote: »

Washing up liquid usually contains salt, and is corrosive. It is also insufficiently viscous to stay on the joint making it more likely it will run off and a leak will be missed. Proper leak detector spray should be used.

Well, viscosity can vary depending on amount of water added. Just tried a bit of fairy and it's not salty at all... (only joking ).
I wish plumbers always wipe excessive soldering flux after themselves. Looking at the pipework, I can see quite a few green spots around joints .

Nevertheless, I get your point. Every job has to be done properly, whether its a DIYer or pro. The difference is though, tradesmen do it for money and speed does matter. People like me are ready to go an extra mile and spend extra hour to make it as neat as poss and to be 100% sure it's safe.

ollski

Foxana wrote: »

At 20 mbars (normal domestic gas pressure) the leak has to really build up for a looooong time to make a big bang

Not quite sure what you mean here, an open ended 35mm copper gas pipe would still only be under 20mb of pressure but wouldn't take many minutes to fill an average living room with enough gas to achieve an explosive mixture.

Foxana

ollski wrote: »

Not quite sure what you mean here

My point was that if you do something on the gas pipework (something like hard-connecting a new hob), open the gas valve, check the gas meter for leakage and there is a leak slightly above norm then it's OK to leave the valve in ON position, so you can go and find an issue instead of calling emergency help line and evacuating the whole family.
Again, common sense is the king. Natural gas is lighter than air so dissipates quickly. Nowadays it's even got smell added to enhances its safety, so there is nothing to be scared of. Just need to double and triple check.

P.S. Sorry for the off-topic, but it always makes me laugh when someone tells me stories that certain things aren't for ordinary people but only highly-trained professionals.

One day we'll have highly trained shopping pros to go out and buy things for you, cause there is a risk of buying wrong staff and consequently dying.

Please, don't discourage people to go out and get familiar with the world we live in. Armageddon is coming in 2012... Remember? There will be no British Gas engineer soon

ollski

Foxana I don't discourage anyone from anything, in fact if you see some of my posts on other diy forums I am always in the doghouse for offering advice on things other gas engineers may find inappropriate, but.....what is the norm?, I'm sure you know on new gas pipework it is 0mb drop. Yes the gas will rise, probably in the cavity or under floor voids where it's installed or any other small space usually with the electrical wires, swtches and potential sources of ignition. Of course there is no risk until it reaches a flammability level of between 5 - 15% dilution in air. Ah well as long as your house is insured for diy gas work I guess it's fine.

Foxana

Oh...yeah... you've started that

Insurance and certification - the biggest scum of them all. Tell me please, what can you do in you own house without being insured?

I hope we are still allowed to do a bit of painting. But don't you dare to paint outside walls. Was told that it needs council approval. Not to mention fully insured scaffolding/tower ;(

ollski

I agree but I'm talking about how things are not how they should be.

jalexa

ollski wrote: »

as your house is insured for diy gas work I guess it's fine.

Well I have searched my policy document and can find no reference to "diy" or similar. Perhaps that would be captured by other wording except I worry that a "competence" test might also fail incompetent tradesmen.

ollski

jalexa wrote: »

Well I have searched my policy document and can find no reference to "diy" or similar. Perhaps that would be captured by other wording except I worry that a "competence" test might also fail incompetent tradesmen.

Nice one, you may be covered if you blow it up. A registered gas installer will have a certificate of competence which lasts for 5 years, weather or not he practices in a competent manner is irrelevant.

I honestly don't care what anyone does in their own house and I'm sure the original post around gas leaks was just badly written, but it referred to a gas leak at 20mb being ok, I am pointing out a) it is the volume that determines the amount of gas much more than the pressure, b) very low concentrations of gas in air make an explosive mixture, c) gas rises and gets trapped.

We're off topic anyway.