Special EMC laws for streetlighting

[ocset]

Hi,
Supposing a streetlight failed radiated emissions, and also failed conducted emissions above 25MHz.
A streetlight  is typically located up a pole, with a few metres of mains cable connected to it….a 20MHz  conducted disturbance is not going to propagate far back into the mains cabling. Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.
As such, do you think there is scope for creating a clause in the EMC laws for the purpose of streetlighting?...ie, making the  EMC pass criteria less stringent  for streetlighting?

[Monkeh]

I think there's scope for you doing your job properly.

[ocset]

Thanks, but it is interesting, should all products, regardless of use case, and regardless of sales volume, ...should they all need to conform to exactly  the same EMC laws, ie  The Standards?

I know from experience that vast amounts of products do not conform to the standards, but it kind of gets "swept under the carpet"...for example, many electronics detonators used in building destruction do not conform to EMC laws.

[drussell]

Everyone should change their regulations (which are there for a reason) because you cannot figure out how to design power supplies properly??!   

[Benta]

Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.

No, but it is going to be right in front of someone's house and can disturb radio and TV reception. There's a reason that EMC is much more stringent for consumer goods than industrial applications.

[Benta]

Everyone should change their regulations (which are there for a reason) because you cannot figure out how to design power supplies properly??!   

My thoughts exactly: 

[dmills]

25MHz you say, so say a wavelength of ~12M, a big metal pole maybe say 7.5M tall, what could possibly go wrong (Think 5/8th wave radiator)?
3rd Harmonic will be in band I PMR, 4th harmonic will be in the FM BCB, 5th possibly in the aircraft communications band....

It is not like these things are stupidly space constrained, just do it right already.
You have more problems getting an EMC pass then any other three engineers I know, hitting the books may pay some serious dividends.

Maybe time to hit the books, Ott has interesting things to say and you should be able to get the company to buy them for the company engineering library.

[MrMobodies]

It certainly interferes with my eyes as I feel strain.

I am finding I have to either wear a cap or put my hood down due to brightness.

They are not bothering to put a diffuser in many of them like in the previous lamps and it is an eye hurter for me.
Now they are in busses and cars and some of them are so bright in daylight, look away and I see an after image of the dots.
Their should be regulations on the diffuser and brightness.

I have complained about missing diffuser on the one on my street to the council many times and it falls on death ears.
They did do something they raised the lamp higher so I not see it in the attic.
The ones on the road did have diffusers after a year they were put up or replaced.

I suspect they are trying to save money and power.

[Whales]

Hi,
Supposing a streetlight failed radiated emissions, and also failed conducted emissions above 25MHz.
A streetlight  is typically located up a pole, with a few metres of mains cable connected to it….a 20MHz  conducted disturbance is not going to propagate far back into the mains cabling. Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.
As such, do you think there is scope for creating a clause in the EMC laws for the purpose of streetlighting?...ie, making the  EMC pass criteria less stringent  for streetlighting?

The original reasoning is more important than the regulations themselves.  The regulations are a second step.

Step (1) Make sure your device does not cause issues for other people
Step (2) Make sure your device meets regulations

If the conducted emissions are contained and attenuated to acceptable levels in the installs: awesome.
If the radiated emissions are not kept in check too: not good.

Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.

Alas your streetlights will however interfere with radio reception.  It might not be life threatening, but that doesn't meet it's ethical or practical.

[james_s]

Absolutely not. The world is already so full of poorly designed garbage switchmode power supplies from China that I can hardly do any shortwave listening anywhere near civilization anymore, it has gotten ridiculous. There's no reason streetlights should be allowed to spew even more RF interference into the air. The regulations exist for a reason, IMHO they're not stringent enough.

[coppice]

Thanks, but it is interesting, should all products, regardless of use case, and regardless of sales volume, ...should they all need to conform to exactly  the same EMC laws, ie  The Standards?

Not all products have to comply with the same EMC specifications. You are only looking at the basic specs for general purpose devices. Many things are required to meet higher standards, which can be tough to meet. If you can't meet the current basic EMC specifications you have no place being in the electronics industry.

[Echo88]

Can somebody please toss his employer an e-mail with the posts of treez, so that he may get him a more suitable job position.  I remember at least three threads about this stuff, its getting worrysome.

[tggzzz]

If at first you don't get the right answer, simply ask the question again.

That's the way cat food manufacturers used to be able to claim "8 out of 10 owners said their cats preferred it".

As for telling his employers, I'm against doxing. (And yes, I do reaslise the suggestion wasn't serious!)

OTOH, there can't be many people in the country with his experience, nor that many potential employers. It wouldn't surprise me if a potential employer matched a CV to all his threads.

[Brumby]

Less stringent EMC regulations about a source ... which is elevated ... and has multiple installations in reasonably close proximity ... when there are engineering solutions?

That's along the same lines of thinking as asking the NRC to let you build a nuclear reactor that has no purposely included shielding - and you want someone to agree that regular building materials will be good enough, just because you can't get your head around doing it properly.

Just ....  NO!

[station240]

Supposing a streetlight failed radiated emissions, and also failed conducted emissions above 25MHz.

How did you manage to get above 25MHz conducted emissions with a street light?
I mean there is no way your using that as a switching frequency, so it's got to be bad design somewhere.

https://www.ofcom.org.uk/__data/assets/pdf_file/0016/103309/uk-fat-2017.pdf
I'm sure no one will mind you jamming:
STANDARD FREQUENCY AND TIME SIGNAL
Space research
MOBILE
MARITIME MOBILE
RADIO ASTRONOMY
AMATEUR
AMATEUR-SATELLITE
etc etc

[DeanA]

Hi,

There are already two levels of emissions standards you can meet:
EN/AS/NZS 61000.6.3:2012
Electromagnetic compatibility (EMC) - Generic standards - Emission standard for residential, commercial and light-industrial environments

or

EN/AS/NZS 61000.6.4:2012
Electromagnetic compatibility (EMC) - Generic standards - Emission standard for industrial environments

There are class A and Class B levels that can be met within those standards too from memory.

In Australia AS/NZS 1158.6 – Lighting for Roads and Public Spaces, should tell you which of the above you need to comply with.

If the product does not comply with the required standards you probably won't win any tenders.

Have you passed all the LED thermal and lifetime requirements such as LM80 tests with TM21 projections and an ISTM test?

Regards,
Dean

[SiliconWizard]

Obviously, streelights are everywhere (unfortunately they are becoming weirdly rampant). They could interfere with all kinds of radio equipments and TV reception.
In crowded areas, they are placed very close to residential and office buildings.

You think EMC is just for aeroplanes and hospitals?

[langwadt]

Hi,
Supposing a streetlight failed radiated emissions, and also failed conducted emissions above 25MHz.
A streetlight  is typically located up a pole, with a few metres of mains cable connected to it….a 20MHz  conducted disturbance is not going to propagate far back into the mains cabling. Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.
As such, do you think there is scope for creating a clause in the EMC laws for the purpose of streetlighting?...ie, making the  EMC pass criteria less stringent  for streetlighting?

just buy a working compliant design from China?

[coppercone2]

NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.
If you believe this to be in error, please contact the moderator involved.
An optional additional explanation is:

[perieanuo]

Hi,
Supposing a streetlight failed radiated emissions, and also failed conducted emissions above 25MHz.
A streetlight  is typically located up a pole, with a few metres of mains cable connected to it….a 20MHz  conducted disturbance is not going to propagate far back into the mains cabling. Also, regarding radiated emissions, a streetlight is not going to get taken into  a hospital where it may interfere with sensitive medical  equipment…neither is a streetlight going to get taken on an aeroplane where it may crash the flight computer.
As such, do you think there is scope for creating a clause in the EMC laws for the purpose of streetlighting?...ie, making the  EMC pass criteria less stringent  for streetlighting?

Maybe yes, maybe no...Sometime an architect will come up with some crazy placement idea for your lamps and then, EMC matters, 1 meter you may have some person with a pacemaker or I dont now what else.you don't rely on power cable to eat your emissions...
My ex boss did the same mistake...and then he was blaming the testing person it was stupid.
Just treat the problem...


Envoyé de mon iPad en utilisant Tapatalk

[ocset]

Thanks, we have a common mode problem, but have little room for adding Y capacitors across the transformers, as well as the ones we already have in the AC mains filter part. Also, we have no room in the bobbins of our transformers for any shield windings. Also, its too expensive to connect the ferrite core of the transformer to a quiet node.
We dont have any more room to increase the size of the common mode choke and Y capacitors, or add a second common mode choke.
We want to put a thermal pad to insulate the FET heatsink from the FET drain, but again,  its more expense on an already tight budget.
We'd also like to space apart our AC mains filter components to limit coupling of emissions round the common mode choke etc, but we dont have the money to be able to increase baord size to do this.
Also, the added expense of twisting the wires off to the LED bank is yet another assembly cost, we'd rather see if we can get a pass with them untwisted, though we expect to be pulled up on this one.

Also, we’d like to bring over a suitably insulated and protected earthing wire across from the earth connection on the primary side of the PCB to the secondary, but again, its too expensive.

[drussell]

Sounds like a complete re-think and re-design are in order.

 

[mikeselectricstuff]

As streetlights are used in multiples, and are on for extended periods of time, any EMC issues are potentially worse than other random products.
The column  will provide some shielding, unless it's concrete or fibreglass....
And any conducted noise will be running in cables alongside other power and comms cabling in the street, and in some cases these may be running overhead instead of buried.

So no, nobody's going to change the regs to cope with companies that don't have sufficient resources to produce compliant products.

Maybe if nobody could produce  compliant unit because of major fundamental limitations, and there was  a compelling reason for energy saving, that might justify a revisiting of the standards, but that's not the case here.

[tom66]

IIRC, luminaires actually have stricter EMC requirements because they're viewed as being more likely to be permanently on.

[chris_leyson]

Try a small ferrite ring on the earth wire, you might need two turns. MnZn if its at tens of MHz or NiZn if it's higher.