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 Proper mains earthing of vintage radios
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 Return to top of page · Post #: 1 · Written at 11:25:56 AM on 21 August 2020.
Simplex's Gravatar
 Location: Bathurst, NSW
 Member since 7 August 2008
 Member #: 336
 Postcount: 336

Soon to start work on valve radio and first thing is to replace the mains cord and plug. There is a standard of nuts, bolts , washers and lugs for the proper earthing under current electrical standards.

Could someone tell me what they are where to get the various bits. A electrical wholesaler ??

Thanks.


 
 Return to top of page · Post #: 2 · Written at 11:45:09 AM on 21 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

Don't solder, but use crimped on eye terminal bolted tightly to the chassis. I also use a star/lock washer between nut and chassis.

https://usercontent2.hubstatic.com/12194477_f1024.jpg

Eye terminals are available at Jaycar, auto supplies, etc. Lock washers are getting harder to find these days, but RS has them: https://au.rs-online.com/web/p/lock-washers/0276869/


 
 Return to top of page · Post #: 3 · Written at 12:35:23 PM on 21 August 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1910

I've always wondered about the logic of the crimp, don't solder, rule.

I assume it's to protect against a poorly-made solder joint.
Isn't a poorly-implemented crimp just as likely?


 
 Return to top of page · Post #: 4 · Written at 12:51:04 PM on 21 August 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 1993

When I worked building the sports cars ,The boss would not allow crimping due to the vibration. So all connectors were solder ..
Not a Radio I know.
I'm not a Fan of crimping though .But the Rules on Radio would be very different I imagine.


Pete


 
 Return to top of page · Post #: 5 · Written at 1:07:22 PM on 21 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

I believe that the no solder rule relates to the possibility of melting under fault current. I think it derives from house/building earth connection rules.


 
 Return to top of page · Post #: 6 · Written at 1:27:55 PM on 21 August 2020.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6352

The thing is, solder on earth connections is only a new rule. We've survived quite well with soldered joints for decades and it was once actually recommended, even inside the switchboard back before the days of busbars.

Ian's comment on a badly made joint is probably what made whoever decided on banning soldered joints go about it. If two wires are put alongside each other and soldered, there is a slight chance the solder may melt before a fuse or breaker trips. If the conductors are twisted together and soldered then enough current will flow to trip a fuse or breaker without causing a meltdown. Even if the solder was 'dry' it would still work because there is enough 'meat' in contact to bypass the lead and tin.

Now, the trick is, where are the rules? Are they state-based regulations like lead tagging rules or are they given out by the Commonwealth? People often make the mistake of saying something is illegal when it may not be. I am not up to date on them so I won't say one way or another but one thing is for sure, all types of joints can be secure or defective, it depends entirely on the attitude of the person doing the job.

Some regulations in AS 3000 (not relevant to this issue) have been relaxed in the most recent version, including that there is no longer a requirement to use 2-screw BP connectors on household mains wiring. I still use them out of habit but it is no longer a requirement under that standard.

One other thing, to do with mains flexes, is that you'll have a choice of installing a new grommet with a cable clamp or using a cable gland. I prefer the former because it allows the radio to look a bit more authentic. Some prefer glands because it is simpler. Neither are better than the other electricly though and it is just a matter of personal taste as to what you will end up using.


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A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 7 · Written at 1:50:52 PM on 21 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

there is no longer a requirement to use 2-screw BP connectors on household mains wiring.

I guess you are referring to earth wire connections. Junction boxes still come with that type of BP for earthing, but seems that will change.

Now, the trick is, where are the rules?

Good question. I have never been able to find black letter law relating to appliance earthing, although it may reside within the wiring rules -- I don't have a recent edition to hand.

I have suspected that it was an imported rule from the EU.


 
 Return to top of page · Post #: 8 · Written at 1:56:55 PM on 21 August 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 1993

On the Topic of 240, because I'm working outside building a shed I want to buy a portable RCD plug board. I should have bought one long before now particularly with my little knowledge,,, Anyway I go to Bunnings and their out of stock !!!!. I will have to buy it off Ebay.
It's the same story in every shop here . I went to Kmart to buy pearl a kids belt and all the shelves are empty....no stock anywhere...
I didn't go to Total tools and see if they had any though . Too cold and rainy here.


Pete


 
 Return to top of page · Post #: 9 · Written at 1:58:16 PM on 21 August 2020.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6352

Appliances are built to different standards, though I am not sure which one applies because I've never bothered to research it.

Clipsal J-boxes now come with four single screw BPs and they are horrible things. They should go back to the previous pattern because it was better quality.


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A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 10 · Written at 2:01:03 PM on 21 August 2020.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6352

Get it from TLE, Johnny Turk, L&H, etc.

Bunnings always run out of things. Their advertised stock policy is BS. That router I bought the other day came from the new Gladesville store, which opened about two weeks ago. It's the only Bunnings in this area that even had that tool in stock. I impulse-purchased because I knew that it'd be a while before I'd be able to buy one without resorting to Ebay or visiting Bunnings' special order desk.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 11 · Written at 2:10:59 PM on 21 August 2020.
Vintage Pete's avatar
 Location: Albury, NSW
 Member since 1 May 2016
 Member #: 1919
 Postcount: 1993

Brad,
Yes, you recommend I should buy one some time back and your right.
I will get one
Years ago I cut through a Cord at work with a 10 inch angle Grinder.. I did a very nice ballet dance across the work shop towards the door.

Pete


 
 Return to top of page · Post #: 12 · Written at 3:06:51 PM on 21 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

 
 Return to top of page · Post #: 13 · Written at 3:17:13 PM on 21 August 2020.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 660

In today's houses fitted with earth leakage circuit breakers I cannot see in my wildest dreams how you could have an earth fault that would melt solder. This is my opinion only .
Regards Jim


 
 Return to top of page · Post #: 14 · Written at 3:32:38 PM on 21 August 2020.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1910

Well Pete I certainly won't be losing any sleep about the way I attached the earth connection on your Philips TV chassis, particularly since it was originally 2 core mains flex and Philips transformers have a propensity to spill winding wire out the sides.


 
 Return to top of page · Post #: 15 · Written at 3:33:28 PM on 21 August 2020.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

In today's houses fitted with earth leakage circuit breakers

Not too many of those around anymore is my guess. ELCBs were terrible things; kept tripping because of the earth current present in our MEN system.

RCD's compare the current in active against neutral and trip when there's a difference of 20mA or so.

Earthing rules likely predated RCD's and apply to appliances generally. Think of electric stoves with current ratings of 30 amps or more.


 
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