Front of House Lights Setup

[JohnW2]

I don't really know what "100mA(20V)" means.

I assume it means what it says - that the minimum current is 100mA in a 20V circuit (i.e. 20V across contacts when open).

Surely Minimum Switching Current is either that (at all voltages) or variable.

No - at least, not if the issue in question that that discussed in the link you posted. That problem (of poor electrical contact between contacts, due to surface oxidation etc.) occurs only with small currents in low voltage circuits. Although I don't fully understand it, it is said that higher voltage circuits apparently tend to 'burn off' the oxide coating on the contacts which causes the problem. The minimum current will therefore vary with voltage, and as I said, they have only told us the minimum current at one voltage. I would imagine that at 230V there is probably no (or no significant) 'minimum'.

Other products are similarly specified and some don't mention MSC.

As I said, I personally have rarely seen a 'minimum switching current' specified for either switches or relays.

Kind Regards, John

 

[ban-all-sheds]

I would have the PIR bypass the time control and photocell completely.

Doesn't that mean you would have the PIR turn the lights on during daylight hours?

 

[ban-all-sheds]

I wonder if there's a market for a box which has the following terminals.

230V in.
230V out.
Photocell(s).
PIR(s).

And 4 knobs to set the TOD when you want the lights to go on and off when it's "dark" and ditto when the PIR is triggered.

 

[JohnW2]

I would have the PIR bypass the time control and photocell completely.

Doesn't that mean you would have the PIR turn the lights on during daylight hours?

It would if the PIR itself didn't have a facility to suppress operation during daylight hours - but virtually all of them do have such a facility.

Kind Regards, John

 

[JohnW2]

I wonder if there's a market for a box which has the following terminals.
230V in. ... 230V out. ... Photocell(s). ... PIR(s). ... And 4 knobs to set the TOD when you want the lights to go on and off when it's "dark" and ditto when the PIR is triggered.

As I've just written, you can usually take the PIR(s) out of that equation, because they can 'look after themselves in the manner that nearly all uses will want. Having done that, your 'box' really just becomes the timeswitch we've been talking about (with 'volt-free' contacts if one wishes to avoid the lights coming ion briefly after photocell power-up).

Kind Regards, John

 

[EFLImpudence]

I think this has become over complicated just to avoid photocell power-up.

After all, it may be that the light may be required to come on at, say, 6am on dark mornings for the same effect as in the evening.
That there may be a short power-up period (at 6am or any other time) when already light in the Summer or still light is, in my opinion, of no consequence.

As for saying the photocell is meant to be powered continually; well, that, surely, is just because generally, like any switch, they usually are.

 

[bernardgreen]

This will do the Photocell and Timed OFF function in one unit.

http://www.steinel.de/out/pictures/media/bedien_104275005.pdf

Then a Steinel PIR type IS 180 to provide the motion detection function

http://www.steinel.de/en/Motion-Det.../Infrared-motion-detector-IS-180-2-Black.html

I am 99% certain that the Switched Live from the Photocell can be wired in parallel with the Switched Live from the PIR ( I haven't checked they can )

 

[JohnW2]

I think this has become over complicated just to avoid photocell power-up.

I totally agree. I have lived with a ~30-second 'lights on' at around 2.30pm/3pm for some 25 years and, if anything, find it a 'reassurance' rather than a 'problem'

After all, it may be that the light may be required to come on at, say, 6am on dark mornings for the same effect as in the evening. That there may be a short power-up period (at 6am or any other time) when already light in the Summer or still light is, in my opinion, of no consequence.

Indeed - as you say, of no consequence. If I wanted that functionality, I would merely have to change the 'switch-on time' of my timeswitch to 6am (or whatever), rather than the present 2.30/3.00pm

As for saying the photocell is meant to be powered continually; well, that, surely, is just because generally, like any switch, they usually are.

Only if there is not another switch (or whatever) upstream of it. As I said, I think I did it as I did in the belief that not having the photocell continually powered would extend its life a bit, but that may be a misguided view.

Kind Regards, John

 

[JohnW2]

This will do the Photocell and Timed OFF function in one unit.
http://www.steinel.de/out/pictures/media/bedien_104275005.pdf

Yes, we've discussed that one before. From the absence of any mention of a facility for a remote light sensor, I presume it has to be installed outdoors. I must say that I would have thought it would be simpler to have a clock than to attempt to "compute times (e.g. 1.30am) on the basis of light levels at twilight"! It's not clear as to whether this has electronic or relay switching, is it? ... if the former, then I might not be quite so certain about:

I am 99% certain that the Switched Live from the Photocell can be wired in parallel with the Switched Live from the PIR ( I haven't checked they can )

Kind Regards, John