dumb and dimmer - Page 1
Forum section: electronics / beginners

author: oneohm
author_rank: Newbie
timestamp: April 14, 2017, 09:24:18 pm
content: my household dimmer controls 3 outlet sockets in the walls which may or may not have standard lamps plugged in. As I connect each lamp I would expect the current to be shared between them and hence the light output of each to reduce as the next is added The light output remains unchanged throughout however How is this possible if the dimmer is in series with all three

author: IanB
author_rank: Super Contributor
timestamp: April 14, 2017, 09:28:21 pm
content: Quote from: oneohm on April 14, 2017, 09:24:18 pmQuestion: "How is this possible if the dimmer is in series with all three?"Answer: The dimmer is not in series with all three.The dimmer is in parallel with all three sockets, so that each socket is independent of the other sockets, and each socket individually receives the dimmer output.

author: jeroen79
author_rank: Frequent Contributor
timestamp: April 15, 2017, 06:41:42 am
content: The dimmer is in series with the lamps.But the lamps are parallel to eachother.So each will draw it's rated current when the dimmer is conducting.

author: ebastler
author_rank: Super Contributor
timestamp: April 15, 2017, 07:57:27 am
content: Quote from: jeroen79 on April 15, 2017, 06:41:42 amRight. And one more thing which the OP may not be aware of: The dimmer isnota variable resistor. (If it were, the OP's concern would be correct.) Rather, it rapidly switches between conducting and not conducting the mains voltage, with each period of the 50Hz or 60Hz mains AC. Therefore, the lamps always "see" a voltage source, and, as stated, will draw their rated current independent of how many lamps are connected in parallel.

author: oneohm
author_rank: Newbie
timestamp: April 15, 2017, 12:20:56 pm
content: thankyou You are a gentleman

author: neko efecktz
author_rank: Regular Contributor
timestamp: April 16, 2017, 03:41:18 am
content: WARNING WILL ROBINSON...You said you have the dimmer controlling wall outlets.This can be very dangerous to anything other than incandesant lamps plugged into these outlets.God only knows what would happen to a switch mode power supply if it was plugged in.Most mains powered house hold items other than refrigerators, microwave ovens dish washers washing machines use switch mode power supplies.Most domestic dimmers are also ONLY CAPABLE of handling up to about 500 watts.They DO NOT operate compact fluorescent bulbs and even LED globes are not the best with a dimmer.ALSO driving a transformer supplied device i.e. stereo amp through a dimmer NOT ON. edited......Check out BIG CLIVEhttps://youtu.be/fWh2obSY0dQhttps://youtu.be/_4PwYm_7HKgaround the 14 minute mark re inductive loads edited......Please reconsider your way of dimming lamps.DIMMING WALL OUTLETS IS A NO NO...BILL.

author: stevelup
author_rank: Regular Contributor
timestamp: April 16, 2017, 10:32:24 am
content: It's quite normal here in the UK to have wall sockets on lighting / dimmer circuits, but we use small round pin 5A sockets to differentiate and ensure inappropriate things are not plugged in.

author: tggzzz
author_rank: Super Contributor
timestamp: April 16, 2017, 11:07:06 am
content: Quote from: stevelup on April 16, 2017, 10:32:24 amReally? I've never seen nor heard of that.Where have you seen that?Has the installation been certified as conforming to the IET Wiring Regulations?

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:17:28 am
content: Quote from: stevelup on April 16, 2017, 10:32:24 amI think you are referring to many decades ago.

author: daveshah
author_rank: Unknown
timestamp: April 16, 2017, 11:24:17 am
content: I've seen sockets like that connected to dimmers (or, not so relevant here, light switches) even in fairly recent installs although I know at least one of those was dodgy (metal switches and dimmers not earthed...). It's certainly a de facto standard if not an official one.

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:26:39 am
content: Last time I saw any mention of these was in a Reader's Digest do it yourself manual from the 19 fifties. No doubt there are plenty of old school people around that would still use these if they could. Personally I don't think I have ever seen 1 or used 1. Perhaps seen on a very old piece of equipment that certainly never seen one in use. I doubt very much that they are currently allowed by official standards.

author: Gyro
author_rank: Super Contributor
timestamp: April 16, 2017, 11:30:02 am
content: Yes, I've seen them (5A round pin) used in hotels too. Not necessarily dimmed, but certainly on a separate light switch. The also prevent customers from plugging anything else in. Presumably they would be even more likely to have to follow current wiring regs.

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:33:14 am
content: So presumably these are the lights only? I've never seen a light sold one on.

author: Gyro
author_rank: Super Contributor
timestamp: April 16, 2017, 11:37:48 am
content: Yes lights only. No, neither have I. Presumably they would be fitted on installation.P.S. I just checked Farnell, they have 5A round pin sockets listed, but no longer stocked (must have been recent though. Presumably they had no demand for them, it would be more likely an electrical distributor product.P.P.S. Yes, current stock at Screwfix...http://www.screwfix.com/p/schneider-electric-lisse-5a-1-gang-round-pin-plug-socket-white/8806j

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:40:03 am
content: Well I assume a different plug is to stop you plugging another device into a dimmed socket but then I liked that you could otherwise use on full power on any socket can't be plugged in. It means that if you have a portable light you also need another socket. It's a bit of a retarded concept in today's day and age particularly as dimmers are for incandescent light bulbs anyway and would work atrociously with LED lights in most cases. If you have a fixed wired dimmer for an LED light I can understand that but portable things like desk lamps should incorporate their own dimmer if one is required.

author: stevelup
author_rank: Regular Contributor
timestamp: April 16, 2017, 11:49:09 am
content: This is absolutely normal on higher end properties. Imagine you've got a very large room with numerous floor standing lights all controlled via a home automation system.Or more simply, you may just want to be able to turn out all the lights in the room from a single switch.Or perhaps bedside lights - so you can turn them on and off from a switch near the entrance to the room.And definitely as mentioned already above, in hotel rooms.Of course it's compliant with the wiring regs - why wouldn't it be?Check out this link.This one supplier stocks around 40 different types in many contemporary designs and colours. It's hardly a dead idea or one from many decades ago. The plugs have sleeved pins and meet current standards as well.

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:50:55 am
content: We obviously I don't travel in such exulted circles

author: Gyro
author_rank: Super Contributor
timestamp: April 16, 2017, 11:55:26 am
content: Quote from: stevelup on April 16, 2017, 11:49:09 amI like the way 16A 415V sockets show up in that search, presumably forverylarge andveryhigh end properties.

author: stevelup
author_rank: Regular Contributor
timestamp: April 16, 2017, 11:56:46 am
content: I tried to narrow the search results down, but lost too many useful results!

author: neko efecktz
author_rank: Regular Contributor
timestamp: April 16, 2017, 11:58:29 am
content: in the fifties wouldn't a wall dimmer have been a rheostat?BILL.

author: Simon
author_rank: Unknown
timestamp: April 16, 2017, 11:59:58 am
content: No but they had 2 different sizes of plugs for different loads. I don't think it was even about lights.Sent from my Moto G (4) using Tapatalk

author: Gyro
author_rank: Super Contributor
timestamp: April 16, 2017, 12:07:20 pm
content: Ooh, I see modern 5A plugs even have sleeved pins now, in line with normal 13A ones...https://www.tlc-direct.co.uk/Products/TLPT5.html

author: Zero999
author_rank: Super Contributor
timestamp: April 16, 2017, 01:15:55 pm
content: Quote from: Gyro on April 16, 2017, 11:55:26 amI've never seen a 16A 3 phase connector in a domestic setting. They are designed for use in industrial applications. Single phase 230V (blue), 110V (yellow) and 24V (violet) are also available. If a house has them, it would be because someone's installed them in their workshop or garage.

author: Gyro
author_rank: Super Contributor
timestamp: April 16, 2017, 01:32:58 pm
content: (obviously weak) joke!

author: tggzzz
author_rank: Super Contributor
timestamp: April 16, 2017, 01:43:26 pm
content: Quote from: stevelup on April 16, 2017, 11:49:09 amThere are manymanyinstallations that are non-compliant; people do strange and dangerous things. Some of them are posted elsewhere on this forum.QuoteShrug.There are many things than can be legallysoldin the UK, but which are illegal touse(or can be illegally used).

author: SeanB
author_rank: Super Contributor
timestamp: April 16, 2017, 03:01:21 pm
content: Common for suspended ceiling installations, so you can just do the wiring for the lights, then later the ceiling and partition fitters come through, put up the framing and suspension frame, and then simply plug the light in ( supplied with a 5A plugtop already on, and with both a kite mark, VDE and other certifications as well) and place in the frame as they go along. No sparky needed to do then, saving a second call out for the lights at the end.Makes an office remodel very easy as well, and still specified here on large installs, though they often put in a special dedicated socket ( not red like the UPS versions) for larger light load units that draw over 5A. makes repairing the lights in a large area easy to repair, as you do not have to drop an entire open office area into darkness to change a ballast.

author: Zero999
author_rank: Super Contributor
timestamp: April 16, 2017, 06:13:17 pm
content: Quote from: SeanB on April 16, 2017, 03:01:21 pmYes, 5A lighting sockets are commonplace in offices but I've never seen them in the domestic environment.

author: SeanB
author_rank: Super Contributor
timestamp: April 16, 2017, 06:28:45 pm
content: Lucky you, I lived in an old building ( built 1939) and I had a few of the original 5A socket outlets there. Did a replace though, as the wiring at least was from the 1970's and was rated for 16A socket outlets, and the fuse box had been replaced with a more modern version with a RCD device. At least I did not have to pull new cables and earth wiring through the steel conduit, which is a pain in older buildings, as they all had 3 wires. Some flats still have the wiring from that time, complete with crumbly gutta percha DCC rubber wire, which tends to shed insulation almost by looking too hard at it. I really dislike that stuff, at least the 1960's 70's PVC only sheds PCB oil in the green goo, and does not go bang in the night and weld into the conduits.Worse is the cheapskates who only replace the active conductor and not the neutral, to keep cost down yet have a working RCD, and you have to work on that polished bovine deposit later.