Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


View this topic in a long page with up to 500 replies per page Create new topic
1 | 2 
1756 posts

Uber Geek
+1 received by user: 917


  Reply # 1382160 9-Sep-2015 07:24
Send private message

That statement isn't entirely correct either I'm afraid.

Circuit breakers are required to not trip at the rated current. At 1.4x the rated current they must trip within 4 hours. (there's more to it, but I cant remember it and I'm not able to look it up right now.

The reason for dropping rewireable fuses are many, but the main ones are.
1) They have a very poor ability to stop high fault currents (about 1.5kA). Under serious fault conditions they may fail to interrupt the current.
2) They are a safety issue. They had to be removed, which allowed contact with live parts. People also wired them incorrectly, leaving ends of fuse wire exposed, which is a significant shock hazard.
3) People can and do, either deliberately or through ignorance put the wrong size fuse wire in them.




Location: Dunedin

Hmm, what to write...
968 posts

Ultimate Geek
+1 received by user: 481

Trusted
Lifetime subscriber

  Reply # 1382175 9-Sep-2015 08:05
Send private message

stuartmac:

Actually I recently  changed to these:
http://www.halcyonlights.co.nz/products/interior-lighting/control-gear/0-70w-electronic-transformer/ They work right down to 0W so are perfect for LED as well, about $10+ from memory... and they are a lovely colour tongue-out


That transformer is 12V AC - is that really suitable for LED? I thought they needed 12V DC.


Replacement type LEDs work fine on AC, the fitting/lamp has a built in rectifier




Matthew


 
 
 
 


965 posts

Ultimate Geek
+1 received by user: 146

UberGroup

  Reply # 1382184 9-Sep-2015 08:35
Send private message

andrewNZ: That statement isn't entirely correct either I'm afraid.

Circuit breakers are required to not trip at the rated current. At 1.4x the rated current they must trip within 4 hours. (there's more to it, but I cant remember it and I'm not able to look it up right now.

The reason for dropping rewireable fuses are many, but the main ones are.
1) They have a very poor ability to stop high fault currents (about 1.5kA). Under serious fault conditions they may fail to interrupt the current.
2) They are a safety issue. They had to be removed, which allowed contact with live parts. People also wired them incorrectly, leaving ends of fuse wire exposed, which is a significant shock hazard.
3) People can and do, either deliberately or through ignorance put the wrong size fuse wire in them.


Lighting circuits are meant to have type B or C tripping curve MCB's, These will trip at 1x for sustained periods, At 1.4x they will trip in under a minute, In a dead short from the device you will see an instant trip once the current reaches 3.2x to 7x.

As long as this unit was attached to a light that wasn't turning on and wasn't still on/working/heating up then i would say the devices multiple fail safes listed on the last page have worked just fine




Most problems are the result of previous solutions...

All comment's I make are my own personal opinion and do not in any way, shape or form reflect the views of current or former employers unless specifically stated 

20700 posts

Uber Geek
+1 received by user: 4013

Trusted
Subscriber

  Reply # 1384692 10-Sep-2015 01:25
Send private message

That one looks more like it was sitting ontop of the halogen lamp.

Do yourself a favour and replace them all, at once. Dont stuff about doing one at a time. The power savings are immense with LED instead of incandesent lamps. No excuse not to, payback is in the order of months in most cases.




Richard rich.ms

5405 posts

Uber Geek
+1 received by user: 2600


  Reply # 1384783 10-Sep-2015 09:48
Send private message

andrewNZ: That statement isn't entirely correct either I'm afraid.

Circuit breakers are required to not trip at the rated current. At 1.4x the rated current they must trip within 4 hours. (there's more to it, but I cant remember it and I'm not able to look it up right now.



I don't think so...
There are different types of breakers with different ratings, but I think the standard domestic type is "C - curve".  It should be marked with the amp rating preceded with a letter, so the MCB should have say "10A" but also if C rated, then "C 10" marked on it, as well as voltage, maximum breaking current rating etc.
Maximum inrush current before tripping for the "C" type is rated at 5-10x rated current for 100ms.  So a 10A breaker should not trip with < 50-100A inrush current over 1/10 second.
Looking at the curve chart, then approx:
At 2x rated current, it should trip in about 2 mins.
At 1.4x rated current, it should trip in about 10 mins.
At >1x rated current, it should trip in one hour.
Those ratings at a standard temp (30 deg C?)

AS/NZS 3111 seems to be the relevant standard.

Edit - read Becarra's post above after posting this.  We don't have the same figure for how long before a B or C breaker will trip at 1.4x current, but the basic idea is the same.
The inrush current/short circuit protection is solenoid actuated. B & C have different trip current ratings for this.  The longer term overload protection is bimettalic strip (thermal) and it looks like they behave much the same when current in overload conditions <3x rating and > 10 seconds.

Hmm, what to write...
968 posts

Ultimate Geek
+1 received by user: 481

Trusted
Lifetime subscriber

  Reply # 1384802 10-Sep-2015 10:06
Send private message

richms: That one looks more like it was sitting ontop of the halogen lamp.

Do yourself a favour and replace them all, at once. Dont stuff about doing one at a time. The power savings are immense with LED instead of incandesent lamps. No excuse not to, payback is in the order of months in most cases.


Obviously it depends on what you pay, but if you replace a 50W halogen and pay around $35 for a high quality fitting and assume driver and the LED and driver use about 10W:

If electricity cost 25cents per kilowatt hour and you are saving 40W per fitting, this means you saving around 1 cent per hour per fitting.

So each fitting will take 3500 hours to pay for itself or 2 years if you use it 4 hours per day.

edit Maths




Matthew


20700 posts

Uber Geek
+1 received by user: 4013

Trusted
Subscriber

  Reply # 1384951 10-Sep-2015 13:02
Send private message

mdooher:
Obviously it depends on what you pay, but if you replace a 50W halogen and pay around $35 for a high quality fitting and assume driver and the LED and driver use about 10W:

If electricity cost 25cents per kilowatt hour and you are saving 40W per fitting, this means you saving around 1 cent per hour per fitting.

So each fitting will take 3500 hours to pay for itself or 2 years if you use it 4 hours per day.

edit Maths


Slap in a $4-5 replacement MR16 and it works out to a few months. There are plenty of decent looking ones in the under $10 range now too. Ones without a diffuser on the front will project more and throw less sideways so are closer to a halogen for beam, better than in many cases. But the cheap pack of 8 from bunnings has its place and will have you saving money instantly.




Richard rich.ms



3361 posts

Uber Geek
+1 received by user: 1004


  Reply # 1400244 5-Oct-2015 13:16
Send private message

nigelj: Might be serious enough to go direct to Energy Safety, especially as you've tried to raise issues with the product in the past.

To report a potentially unsafe product: https://www.energysafety.govt.nz/forms/product-appliance-complaint-form (alternatively ring them).



I sent these guys an email ...they just replied....


Premature failure of the lighting transformers is a consumer guarantees issue, not one that Energy Safety administers.

If you still have a concern we can ask Philips to contact you to help resolve the issue.

We will not however pass on your contact details without your permission. Please advise us by e-mail


So, guess it is not their job. 

gzt

9397 posts

Uber Geek
+1 received by user: 1365


  Reply # 1400268 5-Oct-2015 13:42
One person supports this post
Send private message

Maybe a fire service opinion.

1 | 2 
View this topic in a long page with up to 500 replies per page Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

CPTPP text and National Interest Analysis released for public scrutiny
Posted 21-Feb-2018 19:43


Foodstuffs to trial digitised shopping trolleys
Posted 21-Feb-2018 18:27


2018: The year of zero-login, smart cars & the biometrics of things
Posted 21-Feb-2018 18:25


Intel reimagines data centre storage with new 3D NAND SSDs
Posted 16-Feb-2018 15:21


Ground-breaking business programme begins in Hamilton
Posted 16-Feb-2018 10:18


Government to continue search for first Chief Technology Officer
Posted 12-Feb-2018 20:30


Time to take Appleā€™s iPad Pro seriously
Posted 12-Feb-2018 16:54


New Fujifilm X-A5 brings selfie features to mirrorless camera
Posted 9-Feb-2018 09:12


D-Link ANZ expands connected smart home with new HD Wi-Fi cameras
Posted 9-Feb-2018 09:01


Dragon Professional for Mac V6: Near perfect dictation
Posted 9-Feb-2018 08:26


OPPO announces R11s with claims to be the picture perfect smartphone
Posted 2-Feb-2018 13:28


Vocus Communications wins a place on the TaaS panel
Posted 26-Jan-2018 15:16


SwipedOn raises $1 million capital
Posted 26-Jan-2018 15:15


Slingshot offers unlimited gigabit fibre for under a ton
Posted 25-Jan-2018 13:51


Spark doubles down on wireless broadband
Posted 24-Jan-2018 15:44



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.