kitchen fluorescents - back to the drawing board

[sm_jamieson]

I am trying to wire up some fluorescent tubes in an "exposed" manner (not i= n a "luminaire") above some kitchen units. After my experience with the int= erference caused by Philips HF dimmable ballasts, I just want to know the b= est way of connecting up my tubes without causing RF interference. I do not= care about the dimming feature any more.

Is this possible with HF ballasts (non-dimmables HFs can be pretty cheap), = or should I just get some magnetic switch-start types (i.e. purchase a "gea= r tray") ?

The other option would be to buy 4 "luminaires" but these would be hard to = hide behind the cornice and be very clumsy.

RE: Dimmables, there were in the past some "rapid start" dimmable types tha= t are not HF and will not cause RF emissions - I think Dave Plowmans's setu= p may be these, but they do not seem to be available any more.=20

So, if any of our esteemed panel are doing what I am trying to do, how woul= d you do it, and what equipment would you use ?

By the way, the wiki does not mention the RF emissions problem associated w= ith HF ballasts.=20

This is taking way too much time and effort !

Simon.

[The Nomad]

FWIW

I got cheap HF (non-dimming) ballasts off ebay (I think) and just wired them to a switched feed, and then to the caps to connect to the T5 tubes these 'rest' on top of the cupboards.

No obvious RFI

YMMV

Avpx

[sm_jamieson]

in a "luminaire") above some kitchen units. After my experience with the i= nterference caused by Philips HF dimmable ballasts, I just want to know the= best way of connecting up my tubes without causing RF interference. I do n= ot care about the dimming feature any more.

, or should I just get some magnetic switch-start types (i.e. purchase a "g= ear tray") ?

o hide behind the cornice and be very clumsy.

hat are not HF and will not cause RF emissions - I think Dave Plowmans's se= tup may be these, but they do not seem to be available any more.=20

uld you do it, and what equipment would you use ?

with HF ballasts.=20

Forgot to state. The tubes are T8 36W 4 foot tubes. Simon.

[sm_jamieson]

Do you know what make they are ?

Simon.

[The Nomad]

Various :-)

... and they are on top of cupboards, behind cornice so don't fancy clambering around to find out ...

Avpx

[Bob Minchin]

"luminaire") above some kitchen units. After my experience with the interference caused by Philips HF dimmable ballasts, I just want to know the best way of connecting up my tubes without causing RF interference. I do not care about the dimming feature any more.

should I just get some magnetic switch-start types (i.e. purchase a "gear tray") ?

hide behind the cornice and be very clumsy.

are not HF and will not cause RF emissions - I think Dave Plowmans's setup may be these, but they do not seem to be available any more.

you do it, and what equipment would you use ?

HF ballasts.

I've got 6 high frequency ballasts each running 2 x 5' tubes from ELT. I get no interference on VHF radio, WiFi or phone. They came from RS a few years back but I don't know exactly which part number.

[Andrew Gabriel]

"luminaire") above some kitchen units. After my experience with the interference caused by Philips HF dimmable ballasts, I just want to know the best way of connecting up my tubes without causing RF interference. I do not care about the dimming feature any more.

should I just get some magnetic switch-start types (i.e. purchase a "gear tray") ?

hide behind the cornice and be very clumsy.

are not HF and will not cause RF emissions - I think Dave Plowmans's setup may be these, but they do not seem to be available any more.

you do it, and what equipment would you use ?

HF ballasts.

Unlike conventional phase control dimmers for filament lamps, dimming HF fluorescents (using their built-in dimming controls such as 0-10V control or basic potentiometer, or DALI) does not generate any additional interference over non dimming types.

The problem may be that the signal is too weak in the location. Then when the radio ups its AGC, it will amplify the noise, although if it's happening on FM reception, it sounds more like it's the radio's audio side which is picking up rather than the radio side.

Old style fluorescent dimming uses phase control dimmers (with a rapid-start transformer, as you say). Old style ballasts are on their way out, and dimming versions vanished years ago. You could easily make a rapid-start transformer from a couple of LV transformers (or just one with a pair of well isolated windings) - I did that as a teenager. You will need a ballast which doesn't overheat when used on a dimmer, and a dimmer which can handle inductive loads.

has some very old notes of mine (and others).

[sm_jamieson]

Not in theory, although as a tube is dimmed the frequency needs to be increased, and the dimming ballasts might operate at a higher frequency generally (note: mine was only tested at 100% output).

Certainly RF emissions from HF ballasts is a well-known problem, usually more of an issue with the high powers used by "growers" of controlled substances though. It is apparently used to detect some of the offenders, at least in the US.

The radio is cheap, but the radio 4 signal does not appear to be weak. Winding the mains supply cable though a large ferrite a few times got rid of most of the interference, but running on batteries did not. I tried another more expensive radio and the interference did not seem quite as bad, but still unacceptable.

The ballasts were dual ballasts which might produce more interference. However, the interference I experienced seems worse than most people are describing. I did notice a comment in the datasheet saying "EMC precautions must be taken", which I did not see in any other ballast makes. But most said "suitable for use in a type 1 enclosure" (earthed box), whilst one said "suitable for use in type 2 enclosure" (double insulated so not necessarily earthed).

Interesting, but I definitely don't have time to do stuff like that these days. Simon.

[Dave Plowman (News)]

Just because RF can be picked up with specialised equipment doesn't mean it will be a problem to a domestic FM receiver.

[sm_jamieson]

Quite true.

There seems to be a general expectation (and the feedback from Philips stat= ed) that the HF ballasts and wiring should be inside an earthed luminaire a= nd this is probably how they are tested. So it is hit and miss whether the = performance would be acceptable when "exposed".=20

Interestingly, the ballasts outside of the luminaire might not be lawful (I= know nothing about the emissions regulations) and may not comply with the EU standards. This could make the installer liable in the unlikely event th= at this led to a serious incident - more so if the work was being paid for. Probably in a similar category to boosting you wifi beyond legal limits.

Another way of discussing this - would a proper electrician wire up ballast= s exposed in this manner ?

Simon.

Simon.

[sm_jamieson]

in a "luminaire") above some kitchen units. After my experience with the i= nterference caused by Philips HF dimmable ballasts, I just want to know the= best way of connecting up my tubes without causing RF interference. I do n= ot care about the dimming feature any more.

, or should I just get some magnetic switch-start types (i.e. purchase a "g= ear tray") ?

o hide behind the cornice and be very clumsy.

hat are not HF and will not cause RF emissions - I think Dave Plowmans's se= tup may be these, but they do not seem to be available any more.=20

uld you do it, and what equipment would you use ?

with HF ballasts.=20

Well, you can get HF ballast "gear trays" that contain an electronic ballas= t and flying leads attached to tube caps, so they are obviously designed to= be used in an exposed location (not inside a luminaire), so presumably the= ballasts must not cause interference in this configuration. The local electrical wholesaler sells "tamlite" gear trays so I shall get o= ne and try it. Simon.