Voltage Regulator Addendum

[Tall Tim]

Addendum to this excellent post:  

 

My wife found another option from a Thai company called CBC (http://www.cbcinter.co.th/product-category/เครื่องปรับแรงดันไฟฟ้า/). Although a bit more expensive, the 20kVA model includes MOV (surge protection) as well as under/over voltage protection. You have to buy and install these separately for the VEG and LIOA stabilizers. The displays are also more informative with several other useful status indicators. The engineer K. Maetee speaks English and they deliver all around Thailand, or you can hunt it down on Lazada (good luck with the search engine).

 

In my area, Global is only selling aluminum cable in this size. However, there are some places selling copper cable per meter (instead of full roll) at very reasonable prices. If you're at the wood area in Bangkok (Bang Pho) then just Somboon Electric is close by - about 200m down the road from the new Tao Poon MRT station. Also has lugs with color-coded rubber hoods.

 

PEA also very helpful when requesting to disconnect supply at meter while I mess around in distribution box (due to layout, have to re-route cable from meter to a new double-pole breaker, then to the stabilizer and back to box). Apparently just need to call and make a booking and they will come around. However, they won't wait for me to complete the change over, have to make a separate request once first part is done. They thought that might be a bit inconvenient and asked why I just don't disconnect the live wires the box and tape them over while I'm working with them....  think I prefer invonvenient!

 

[Crossy]

1 minute ago, Tall Tim said:

PEA also very helpful when requesting to disconnect supply at meter while I mess around in distribution box

 

They are probably suffering from shock (not the electric kind) at being asked.

 

Not one of the local sparkies I've been involved with has hesitated to pull the wires at the outgoing side of the meter even on the one occasion that a seal was fitted.

 

If you do enough prep you should be able to get them to disconnect, have a cup of tea whilst you move to the new breaker, then re-connect.

 

If you have plastic distribution boxes there's not really too much risk in doing the switch over live (get your local sparks to do it mind). I would not attempt it with a metal box, too much earthed metal around.

 

 

 

[bankruatsteve]

For me:  MOV "protection" for transient surges is not something I would pay much extra to have.  Direct or near lightning will fry almost everything regardless.  My VEG trips off on under/over voltage.  And, Cu is not better than Al, it just comes in a smaller package for the same resistance.  After all, HV lines are almost always Al.

[Crossy]

1 hour ago, bankruatsteve said:

And, Cu is not better than Al, it just comes in a smaller package for the same resistance. 

 

Whilst this is completely correct, it is important to understand that putting an Al cable into a fitting meant for Cu (and few domestic bits are Al rated) can cause problems such as loosening connections over time with the resultant fizzing and potential conflagration.

 

Personally I won't have Al inside the building. Run Al from the street then splice a short length of Cu to the end using the correct grease-filled crimps and run that to your board. All the advantages (cost) and if a joint goes awry it's outside.

  

For those that don't know Al = alumin(i)um cable, Cu = copper cable ????

 

 

[johng]

Is there any "corrosion" between dissimilar metals, maybe that's what the grease is for ?

[impulse]

3 hours ago, bankruatsteve said:

For me:  MOV "protection" for transient surges is not something I would pay much extra to have.  Direct or near lightning will fry almost everything regardless.  My VEG trips off on under/over voltage.  And, Cu is not better than Al, it just comes in a smaller package for the same resistance.  After all, HV lines are almost always Al.

 

Lightning isn't the main focus of an MOV based TVSS (Transient Voltage Surge Suppressor).  It's the incessant surges and spikes every time your's or your neighbor's air con or other motor(s) turn on and off, all of which have a cumulative effect on the equipment your TVSS is protecting (and the MOV itself).  The failures aren't catastrophic like lightning, but delicate electronic stuff wears out quicker.

 

That said, you have to remember that every time an MOV based TVSS takes a surge, some of the molecules re-align and eventually the unit no longer functions as intended.  So the MOV itself needs to be on your list of things to maintain and replace when they wear out.  Unfortunately, they usually (at best) have an LED bulb that goes out when they need replacing, and it's hard to tell if it's the MOV or the LED bulb that wore out.

 

Cu is much better than Al when it comes to corrosion.  Even more so when it's in contact with copper connections which are inherently more "noble" than aluminum cable.  Put aluminum, copper and humidity together in a junction box, and the aluminum is going to corrode away.  If your system is properly designed, great.  Aluminum is okay. That's why aluminum is okay for the distribution system.  But that's only if it's designed to use aluminum, not pulling Al wires as an after thought.

 

 

[wgdanson]

8 minutes ago, impulse said:

 

Lightning isn't the main focus of an MOV based TVSS (Transient Voltage Surge Suppressor).  It's the incessant surges and spikes every time your's or your neighbor's air con or other motor(s) turn on and off, all of which have a cumulative effect on the equipment your TVSS is protecting (and the MOV itself).  The failures aren't catastrophic like lightning, but delicate electronic stuff wears out quicker.

 

That said, you have to remember that every time an MOV based TVSS takes a surge, some of the molecules re-align and eventually the unit no longer functions as intended.  So the MOV itself needs to be on your list of things to maintain and replace when they wear out.  Unfortunately, they usually (at best) have an LED bulb that goes out when they need replacing, and it's hard to tell if it's the MOV or the LED bulb that wore out.

 

Cu is much better than Al when it comes to corrosion.  Even more so when it's in contact with copper connections which are inherently more "noble" than aluminum cable.  Put aluminum, copper and humidity together in a junction box, and the aluminum is going to corrode away.  If your system is properly designed, great.  Aluminum is okay. That's why aluminum is okay for the distribution system.  But that's only if it's designed to use aluminum, not pulling Al wires as an after thought.

 

 

Are nuclear bombs made from URANUM and PLUTONUM?   LOL

[impulse]

56 minutes ago, wgdanson said:

Are nuclear bombs made from URANUM and PLUTONUM?   LOL

 

Nope.  But in the USA, stuff is made of aluminum.  Not aluminium.

 

[Crossy]

11 hours ago, impulse said:

 

Nope.  But in the USA, stuff is made of aluminum.  Not aluminium.

 

 

When Hans Christian Ørsted first produced the element in 1825 he called it "Aluminum" (yes, the US spelling). Later someone decided that, since other metals had names ending "-- ium" that this was a mistake and so "Aluminium" was born.

 

Now, whether the US decided to stick with the "correct" spelling or simply cannot say "Aluminium" I have no idea, but I would not be surprised if Noah Webster (he of dictionary fame) had something to do with it.

[bankruatsteve]

7 minutes ago, Crossy said:

 

When Hans Christian Ørsted first produced the element in 1825 he called it "Aluminum" (yes, the US spelling). Later someone decided that, since other metals had names ending "-- ium" that this was a mistake and so "Aluminium" was born.

 

Now, whether the US decided to stick with the "correct" spelling or simply cannot say "Aluminium" I have no idea, but I would not be surprised if Noah Webster (he of dictionary fame) had something to do with it.

I didn't bloody know that.