Switchmode PSU to mains wiring

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552 posts

Ultimate Geek

#885426 27-Aug-2013 17:50

BigHammer: If I read that correctly, it would not be illegal to affix a power lead to the above unit. You can even buy leads with the correct terminals already fitted. You will need to connect the earth, and the earth will need to be carried through to the chassis/case if it is of metal construction.

Of course I could be wrong, but that's my interpretation of the above clause.

This type of power supply is not intended to be used without being enclosed. There is no way terminals like this can be left exposed.

The regs say that anyone can wire up anything they want themselves, as long as they don't plug it in until it is tested and tagged as safe by a currently registered electrical worker.

If an registered electrical worker connected this, as it is, without enclosing the supply in a box, they would be struck off and fined if caught.

don't mess with me.... i'm the hd insider....

jpoc

1043 posts

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#885450 27-Aug-2013 18:17

kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

I saw the same thing in my first job after uni. In the building, power came overhead on the roof supports and the sockets were up there. One hero tried to connect the socket overhead to a bank of sockets on a test-bench by means of a double plugged cable.

In another company, the lab tech was given the task of testing some of our prototypes for resistance to bad stuff coming up the power-lead. We had a box that gave you mains voltage and let you twirl some dials to select varying voltage and frequency, and noise spikes. It had three screw terminals on the front for LNE. The tech borrowed a four way extension lead from somewhere and then cut a power cable off some broken device. He stripped the ends off the power lead and screwed it into the mains/noise generator and then plugged the, now live plug into the four-way socket extension. That way he still had an exposed plug carrying live power on the end of the four way extension lead. Even better of course was the fact that the bad mains generator could happily kill you without tripping any of the leakage current breakers back on the switchboard.

You would have thought that those companies would have known better. They both sold high tech electronics kit to customers who played with nuclear fusion for a living.

jpoc

1043 posts

Uber Geek

#885451 27-Aug-2013 18:19

hdinsider:
BigHammer: If I read that correctly, it would not be illegal to affix a power lead to the above unit. You can even buy leads with the correct terminals already fitted. You will need to connect the earth, and the earth will need to be carried through to the chassis/case if it is of metal construction.

Of course I could be wrong, but that's my interpretation of the above clause.

This type of power supply is not intended to be used without being enclosed. There is no way terminals like this can be left exposed.

The regs say that anyone can wire up anything they want themselves, as long as they don't plug it in until it is tested and tagged as safe by a currently registered electrical worker.

If an registered electrical worker connected this, as it is, without enclosing the supply in a box, they would be struck off and fined if caught.

How about an exposed PC power supply? I would have thought that would be pretty common.

andrewNZ

2487 posts

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Inactive user

#885454 27-Aug-2013 18:31

jpoc:
hdinsider:
BigHammer: If I read that correctly, it would not be illegal to affix a power lead to the above unit. You can even buy leads with the correct terminals already fitted. You will need to connect the earth, and the earth will need to be carried through to the chassis/case if it is of metal construction.

Of course I could be wrong, but that's my interpretation of the above clause.

This type of power supply is not intended to be used without being enclosed. There is no way terminals like this can be left exposed.

The regs say that anyone can wire up anything they want themselves, as long as they don't plug it in until it is tested and tagged as safe by a currently registered electrical worker.

If an registered electrical worker connected this, as it is, without enclosing the supply in a box, they would be struck off and fined if caught.

How about an exposed PC power supply? I would have thought that would be pretty common.

No, PC power supplies don't have terminals at all, you plug the lead in, there are no exposed live parts.
Generally speaking, to be considered safe you shouldn't even be able to touch the individual coloured wires within a cable carrying mains voltage.

Bung

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#885462 27-Aug-2013 18:50

jpoc: How about an exposed PC power supply? I would have thought that would be pretty common.

A PC power supply is completely enclosed with mains input via an IEC socket. The outputs are ELV.

Stu

Hammered
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#885535 27-Aug-2013 20:42

I didn't suggest a case optional. The only comment was whether the case would be metal or not. Of course anything with mains pins exposed needs to be enclosed.

People often mistake me for an adult because of my age.

Keep calm, and carry on posting.

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hdinsider

552 posts

Ultimate Geek

#885552 27-Aug-2013 20:56

BigHammer: It's not like you're wiring a new bedroom. That would need to be checked and certified before being connected (have wired a detached garage before, and had to do just that). You're connecting a power lead to a device which has been tested and certified.

No. The unit hasn't been certified for use externally. Although it has been tested in the factory, (hopefully!), it has not been electrically tested in it's final location within an earthed enclosure. It will need to be tested for insulation resistance and earth continuity to meet safety specifications once it is installed in an enclosure.

This is where I was thinking you were accepting that it was ok to use by itself, unsafe and unenclosed.

don't mess with me.... i'm the hd insider....

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cisconz

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#885563 27-Aug-2013 21:18

kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

I have a generator changeover switch for that.
Wouldn't that also power the other houses on his phase on his street?
The amount of 3x 10A Plugs to 1x 32A 3Phase socket with tied neutrals is unbelievable.

Hmmmm

jpoc

1043 posts

Uber Geek

#885572 27-Aug-2013 21:45

cisconz:
kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

I have a generator changeover switch for that.
Wouldn't that also power the other houses on his phase on his street?
The amount of 3x 10A Plugs to 1x 32A 3Phase socket with tied neutrals is unbelievable.

I wondered about that but I suspect that the newer smart meters might block it.

hdinsider

552 posts

Ultimate Geek

#885600 27-Aug-2013 22:11

jpoc:
cisconz:
kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

I have a generator changeover switch for that.
Wouldn't that also power the other houses on his phase on his street?
The amount of 3x 10A Plugs to 1x 32A 3Phase socket with tied neutrals is unbelievable.

I wondered about that but I suspect that the newer smart meters might block it.

They wouldn't be able to stop the feed. They're just metering the power consumption. They're only smart in that they send the power usage back to base without needing a meter reader to look.

No one should ever do this to power their house, but if they did, turning off the main switch would stop the power running back up the street.

DON'T EVER DO THIS.

don't mess with me.... i'm the hd insider....

hdinsider

552 posts

Ultimate Geek

#885603 27-Aug-2013 22:17

kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

Shiver indeed. Truly stupid and terrifying. Kiwitrc, please try to stop that guy!

don't mess with me.... i'm the hd insider....

PaulBags

809 posts

Ultimate Geek
Inactive user

#885671 28-Aug-2013 08:39

hdinsider:
jpoc:
cisconz:
kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

I have a generator changeover switch for that.
Wouldn't that also power the other houses on his phase on his street?
The amount of 3x 10A Plugs to 1x 32A 3Phase socket with tied neutrals is unbelievable.

I wondered about that but I suspect that the newer smart meters might block it.

They wouldn't be able to stop the feed. They're just metering the power consumption. They're only smart in that they send the power usage back to base without needing a meter reader to look.

No one should ever do this to power their house, but if they did, turning off the main switch would stop the power running back up the street.

DON'T EVER DO THIS.

Would running it like that also prevent the other circuit breakers from being effective?

Back to the power supply: if you did a DIY job on the power supply, installing it in an enclosure and giving yourself some leads or sockets for the DC connections so you don't have to open it up again (I'm assuming you can't open it again once tested?), could you then just take/send it somewhere to get tested; and how much might the testing alone cost? Would the internals of the enclosure need to be accessible for testing? If it needs to be opened to test and you can't open it after testing, then you can't ever permanently seal it, if you wanted to.
If you can't open it up again, how would you use the voltage adjust, especially if you can't power it up before proper testing?

kiwitrc

4123 posts

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#885688 28-Aug-2013 09:01

hdinsider:
kiwitrc: Speaking of things that make you sh!t yourself, the guy who mows our private road berm was telling me a good trick during a power outage.

He has a generator and figured out if you wire an extension cable with a plug at both ends then you can plug it into your house wiring when the power is off and run the whole house from the generator.

"Shiver"

Shiver indeed. Truly stupid and terrifying. Kiwitrc, please try to stop that guy!

Why, its just Darwins law in action?

He did say he turned the mains power into the house off first so I guess he wont be powering other houses or killing the linesman down the road fixing it. I did actually say that was incredibly dangerous and he shouldnt do it.

andrewNZ

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#885689 28-Aug-2013 09:03

First let's make a safety statement.
Electricity kills, PLEASE, for the love of orange juice, be safe. If you don't know about something, ask an electrician for advice. If you reach the point where you think you know enough and electricity doesn't scare you any more, you've reached that point where you know just enough to be dangerous!

There's a fair bit of misinformation in this thread... The majority of the electricity act and regs content refers specifically to Prescribed Electrical Work (PEW), this *probably* isn't PEW. It is however ALWAYS a good idea to err on the safe side.

Answering the above question:
It would only need retesting if any of the mains wiring was altered, and there would be no reason to do that.
For something like this, you're better off getting a local sparky to check and test it, but it's really only a 15 minute job.

andrewNZ

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#885690 28-Aug-2013 09:05

If anyone is interested NZ Electrical Code of Practice (NZECP) 51, is the Electrical Code of Practice for home owners and occupiers. It contains a lot of good information to help you stay safe.

Parent page here http://www.med.govt.nz/energysafety/legislation-policy/electricity-acts-regulations-codes/standards-and-codes-of-practice/new-zealand-electrical-codes-of-practice

NZECP 51 here http://www.med.govt.nz/energysafety/documents/legislation-policy/electricity-act-regulations-codes/standards-and-codes-of-practice/NZECP%2051%202004%20New%20Zealand%20Electrical%20Code%20of%20Practice%20for%20Homeowner%20Occupiers%20Electrical%20Wiring%20Work%20in%20Domestic%20Installations%20%20-%20Published%2027%20July%202004%20.pdf

Edit: added links.

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