Fuses, Breakers, Amps, Max Load... Crossy!

[Pacificperson]

A properly placed gecko might.

[jbrain]

^ Would also like to say that an ingress of water is highly unlikely to generate such fault currents.

Give it a thorough examination on Monday so that you can give a proper report here later, at the same time I will do similar with the aged portwine

[Forkinhades]

^ examining the portwine, sounds much more fun

[wayned]

^ examining the portwine, sounds much more fun

Why don't you just move in with him and change your logon name? Could be forkinnaam or naaminhades!

[Forkinhades]

^

[Forkinhades]

A properly placed gecko might.

I will have to google the resistence of a gecko

[Crossy]

I suspect that the fried fuseholder was caused by a loose connection quietly fizzing away for a while. It was only noticed when the circuit opened either because the fuse overheated and failed or the arcing points eroded enough to kill the arc.

Naam, has the fuse blown at any other time without burning the holder?

[jbrain]

^ examining the portwine, sounds much more fun

Well Forky, you have to make choices in life.

You choose to be an electrician, while I knew my future would be an alcoholician .

[Forkinhades]

^ goes hand in hand

[Neeps]

Can u guys give us an update. I tried to follow and look at the pics etc and I would like to know outcome. I am a sparky and never seen this set up. Looks a bit overkill......

[Forkinhades]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

[Naam]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

and the three of us never bitched about other TV-members well... perhaps... just a teenie weenie little bit

we should repeat the session one of these days but it is quite difficult to find real old Port in Thailand.

[Naam]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

a genset would have meant excessive additional wiring because the three systems are far apart not to talk about the additional cost. more than 5 years positive experience with my three systems (except for charger breakdowns) did and do not cause any worries about total load.

interesting is the fact that until now i had to change only the battery set that serves my two water supply pumps (2x450W). no problems with the other two battery sets.

[Naam]

Can u guys give us an update. I tried to follow and look at the pics etc and I would like to know outcome. I am a sparky and never seen this set up. Looks a bit overkill......

is it overkill if a 31,000 Baht investment saves you in excess of 31,000 Baht each and every year by not replacing burned relays for aircons and pumps? i don't think so.

[Forkinhades]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

and the three of us never bitched about other TV-members well... perhaps... just a teenie weenie little bit

we should repeat the session one of these days but it is quite difficult to find real old Port in Thailand.

I will make sure that I bring a bottle over with me next time. As you know I will be leaving shortly

[Forkinhades]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

a genset would have meant excessive additional wiring because the three systems are far apart not to talk about the additional cost. more than 5 years positive experience with my three systems (except for charger breakdowns) did and do not cause any worries about total load.

interesting is the fact that until now i had to change only the battery set that serves my two water supply pumps (2x450W). no problems with the other two battery sets.

Ah yes indeed, but a nice 10KVA genset would keep you nice and cool

[Naam]

^ My first thoughts was that the set up was more suitable in a data suite enviroment, than for a home. Then got to thinking of how unstable the PEA supply is, so the system would it seems be doing a good job.

One does wonder though why Naam chose an invertor system, and not a UPS with a genset. He seems to have done his math on the duration of his 320Ah batteries, but I am not sure of the VA of his invertor, and of total loads on them.

To be honest we was all far too busy drinking his 37 year old port, and talking life events rather than looking at or discussing his electrical set up.

a genset would have meant excessive additional wiring because the three systems are far apart not to talk about the additional cost. more than 5 years positive experience with my three systems (except for charger breakdowns) did and do not cause any worries about total load.

interesting is the fact that until now i had to change only the battery set that serves my two water supply pumps (2x450W). no problems with the other two battery sets.

Ah yes indeed, but a nice 10KVA genset would keep you nice and cool

we hardly ever experience that all three phases are missing. one phase working means at least 6 aircons are operational. i discussed installing a genset with TV-member "Genset" two or three years ago. but if need arises (it does not look like at all) it will be something "heavier" than a 10KVA toy. if i recall correctly we considered 48KVA at that time.

[Naam]

big thanks for reviving this archived thread!

being a sparky apprentice, but picking up rather fast, i'd like to report a few "alien" experiences which happened during the last couple of weeks.

-day 1

19.00hrs one phase failed. that happens once in a while and is not considered tragic because it lasts a few minutes or max 2 hours.

21.30 phase not back. main aircon in master-bedroom not working (desaster because i like to go to bed in a real cool room).

21.45 my neighbour confirmed all three phases available, no failure or brown-out of any phase.

22.00 went outside and checked the main supply to the house. result: all three phases ok.

22.10 checked my protective thingy and saw one automatic breaker off. "stupid me!" i thought and flipped the switch up but it did not hold. called my "personal engineering assistant" who arrived 20 minutes later.

22.30-23.00 we are drenched in sweat but did not find any fault. all individual breakers "on", none tripped.

23.05 we opened main supply box keeping on searching.

23.20 one of us measured "failing" phase with a clamp-amp, the other one switched on "MCB whatever-safe-t-cut" during this splitsecond we measured a 110amp flow! measured a dozen times more with the same result.

23.30 called a sparky friend in Germany who couldn't give us any advice.

23.45 assistant reports "have maybe bloken insuration of yellow phase in box up"

23.50 switched main supply off and pulled out the "maybe bloken" cable. indeed! insulation was cut and burnt at one point. reason: the connecting holes of two boxes did not match and the original sparkies rammed three 25mm² cables through a single hole in the upper box where sharp edges cut into the insulation.

diagnosis: 2 years after moving in we built a small staff house and cut out a door to that side. "cutting out" meant that a chap sent by the contractor hacked 5 days, 8 hours a day the wall next to the main boxes. due to some vibrations plus vibrations of a few thousand times door opening and closing the insulation got cut.

24.00 we insulated the cut and rerouted the cable outside the two boxes to take proper care next morning.

day 2

enlarged cut out by connectiong two holes, connected cable properly, did some additional protective work and closed boxes.

day 3,2,4,5,6,7,8,9,10 everything "AOK"

day 11

yellow phase safe-t-cut tripped and shut down same phase again

switched "on" it holds for up to 15 seconds and then trips. measured amps again showing normal 12 amps before tripping.

switched off main power supply and after that tripped breaker. breaker trips! me "how can breaker trip without power?" assistant "bleaker kaput?"

yes, bleaker indeed kaput! replaced, (God willing!) problem solved.

addendum: the photo shows the corrected version (yellow phase down>up in individual enlarged hole).

Edited June 21, 2014 by Naam

[Crossy]

Ouch!

But all too typical here (and India), locals have never seen grommet strip before (I bought some from Ebay). Could have been REALLY nasty if it was the incoming supply (no PEA fuse), with the National Grid behind it that would have been a serious fire!!.

This stuff:-

By the way, all three phases should go through the same hole in a ferrous panel, otherwise you get eddy currents and the panel can get very hot.

[Naam]

Ouch!

But all too typical here (and India), locals have never seen grommet strip before (I bought some from Ebay). Could have been REALLY nasty if it was the incoming supply (no PEA fuse), with the National Grid behind it that would have been a serious fire!!.

This stuff:-

images.jpg

By the way, all three phases should go through the same hole in a ferrous panel, otherwise you get eddy currents and the panel can get very hot.

somehow i had a feeling it's not over monday we will cut again and now i will look up "eddy currents".

[Naam]

AARRRGGGHHH!

The derivation of a useful equation for modelling the effect of eddy currents in a material starts with the differential, magnetostatic form of Ampère's Law,^[9] providing an expression for the magnetizing field H surrounding a current density J:

Taking the curl on both sides of this equation and then using a common vector calculus identity for the curl of the curl results in

From Gauss's law for magnetism, ∇ · H = 0, so

Using Ohm's law, J = σE, which relates current density J to electric field E in terms of a material's conductivity σ, and assuming isotropic homogeneous conductivity, the equation can be written as

Using the differential form of Faraday's law, ∇ × E = −∂B/∂t, this gives

By definition, B = μ₀(H + M), where M is the magnetization of the material and μ₀ is the vacuum permeability. The diffusion equation therefore is

[transam]

I have to pull a ceiling down to find perhaps rat damage or worse, soon..........

[Naam]

I have to pull a ceiling down to find perhaps rat damage or worse, soon..........

worde? the skeleton of your former girlfriend?

[transam]

I have to pull a ceiling down to find perhaps rat damage or worse, soon..........

worde? the skeleton of your former girlfriend?

Naaaaaah, shes in farangland...........

[Crossy]

I have to pull a ceiling down to find perhaps rat damage or worse, soon..........

worde? the skeleton of your former girlfriend?

Naaaaaah, shes in farangland...........

And probably on Facebook, I just got a friend request from my Korean ex, she dumped me 14 years ago.

[Maestro]

AARRRGGGHHH!

The derivation of a useful equation for modelling the effect of eddy currents in a material starts with the differential, magnetostatic form of Ampère's Law,^[9] providing an expression for the magnetizing field H surrounding a current density J:

Taking the curl on both sides of this equation and then using a common vector calculus identity for the curl of the curl results in

From Gauss's law for magnetism, ∇ · H = 0, so

Using Ohm's law, J = σE, which relates current density J to electric field E in terms of a material's conductivity σ, and assuming isotropic homogeneous conductivity, the equation can be written as

Using the differential form of Faraday's law, ∇ × E = −∂B/∂t, this gives

By definition, B = μ₀(H + M), where M is the magnetization of the material and μ₀ is the vacuum permeability. The diffusion equation therefore is

Good gracious! I have a feeling that even knowing rocket science does not help you much to understand those formulas.

Sent from my Nexus 4 using Thaivisa Connect Thailand mobile app

[JesseFrank]

AARRRGGGHHH!

The derivation of a useful equation for modelling the effect of eddy currents in a material starts with the differential, magnetostatic form of Ampère's Law,^[9] providing an expression for the magnetizing field H surrounding a current density J:

Taking the curl on both sides of this equation and then using a common vector calculus identity for the curl of the curl results in

From Gauss's law for magnetism, ∇ · H = 0, so

Using Ohm's law, J = σE, which relates current density J to electric field E in terms of a material's conductivity σ, and assuming isotropic homogeneous conductivity, the equation can be written as

Using the differential form of Faraday's law, ∇ × E = −∂B/∂t, this gives

By definition, B = μ₀(H + M), where M is the magnetization of the material and μ₀ is the vacuum permeability. The diffusion equation therefore is

Would a sparky named Eddy be of any use ? Let me know.

[Tywais]

somehow i had a feeling it's not over monday we will cut again and now i will look up "eddy currents".

Think 'induction heater'.

[Naam]

AARRRGGGHHH!

Would a sparky named Eddy be of any use ? Let me know.

NO! according to Crossy he is the culprit who causes the dangerous currents

[Forkinhades]

^ 555

nice memories of the 20 year old port