DIY AC panel

[chris w]

Thanks, thats very useful but i specifically want to know what type of neons to use to indicate power on and reverse polarity and how they are wired, .....

Any standard neon that already incorporates the current limiting resistor will do. (eg: Maplin code BK52G @ 99 pence each clicky)

 

For "Supply On" wire a neon across the live and neutral after the RCD trip.

 

For "Correct Polarity" wire a neon between live and earth before the RCD trip.

 

If you prefer to have one showing "Incorrect Polarity" then wire a neon between neutral and earth before the RCD trip. This will only illuminate in the event of incorrect polarity. The caution is that it will also not illuminate if the neon fails. You could use one neon for "Correct Polarity" and one for "Incorrect Polarity" if you want "belt and braces"

 

Chris

Edited May 6, 2009 by chris w

[Radiomariner]

On more than one occasions I have seen mains neons fail causing short circuit, usually caused by vibration.

For those concerned about connecting a neon between live and neutral, for example, consider adding a small in-line fuse probably around 300mA. It will probably never blow, but you know you have the protection.

[Phoenix_V]

Thanks to Alan and Chris - really useful practical information, now does anyone know if double pole rcds and mcbs are really required (for the Recreational Craft Directive) and if so recommendations as to exactly what to ask for in the electrical shop?

Edited May 7, 2009 by Phoenix_V

[Gibbo]

On more than one occasions I have seen mains neons fail causing short circuit, usually caused by vibration.

For those concerned about connecting a neon between live and neutral, for example, consider adding a small in-line fuse probably around 300mA. It will probably never blow, but you know you have the protection.

 

Eh?

 

They have a 220k resistor in series with them. The neon going short will do next to nothing. It will end up with a resistor across 230 volts drawing 1mA and dissiptating 230milliwatts. Or have you actually seen the whole thing go short? I've never seen that.

 

Gibbo

 

Thanks, thats very useful but i specifically want to know what type of neons to use to indicate power on and reverse polarity and how they are wired, and also with regard to the mcbs and rcds the RCD (as in Recreational Craft Directive) seems to require double pole units wheras most house wiring uses single pole.

The rcds appear to be available double pole but are really expensive, i just wanted to check I had read it right and they really are required. I presume one just uses two mcbs to obtain a double pole mcb as I cant se 2 pole units?

 

You only need two pole RCDs and MCBs if you don't use a neatral/earth bonded system.

 

Gibbo

[Keeping Up]

Or have you actually seen the whole thing go short? I've never seen that.

Nor have I

[Big Steve]

 

Having got fed up of paying through the nose for Heath Robinson AC panels I decided to do my own.

 

All the parts are off the shelf and the units in their purest form meet the BMEA code of practice and the RCD.

 

If the BMEA code of practice is found a bit lacking for your application and exspansion is needed you will still safely be able to exspand on that following the 16th addition guidance for additional circuits. (At your risk!)

 

If anyone would like the parts list, art work and wiring instructions putting together let me know and I will post them here later. (When I get a few mins to spare!)

 

It definetly provides a cheaper and more flexible solution to the ones for sale for much more.

 

 

Should I be able to see a pretty picture here? I can't.

[Gibbo]

Should I be able to see a pretty picture here? I can't.

 

Might be related to the fact that the post you quoted is over 3 years old

 

Gibbo

[Scotty]

Also, I suspect Gary's images were hosted on the Ledgard Bridge website.

[Big Steve]

That might explain it, I never noticed the date.

[Radiomariner]

Eh?

 

They have a 220k resistor in series with them. The neon going short will do next to nothing. It will end up with a resistor across 230 volts drawing 1mA and dissiptating 230milliwatts. Or have you actually seen the whole thing go short? I've never seen that.

 

Gibbo

 

My post was not for you Gibbo, but in response to those not happy about connecting components direct across the mains.

 

I have seen three. The last one was at least 7 years ago and all had been in service for over ten years. There has been some changes in their design since. The failures were always in an area of high vibration and where ambient temperatures frequently exceed 50 deg C.

Two failed at the connecting pins. My conclusions were that too much heat had been applied when making the original solder connections, thereby damaging the surrounding plastic holding the pins: The heat and vibration did their bit, the fact that these were on removable panels necessitating longer connecting wires, (the insulation of which had gone brittle) causing mechanical stress on the rather fragile pins, which shorted inside the casing, In line before the internal resistor!

I remember these two particularly well because fault detection was not easy as five such multicomponent panels (not all the same) were powered from the same breaker.

The third one, I have not a clue why it failed. It was easy to find by the smoke and the blackened blob of plastic that was left. Had to consult the manuals to find out exactly what the component was!

 

I am quite happy with the neon indicators on my own boat, (No fuse), but I have checked to ensure that the terminal pins do not move when wiggling the wire

 

 

Edited to sort out Gobbo's quotation and correct a couple of typo's

Edited May 9, 2009 by Radiomariner