Apartment - Dishwasher dims lights

pippip

Hi all,

Just wondering could anyone help.

Basically our apartment kitchen has three downlights (Gu10 50w) When all three bulbs are in and the dishwasher is turned on the lights go very dim. If I take a bulb out the remaining two stay at full brightness.

I know it may be hard to tell without testing things but what would peoples best guess be thats causing the problem. Apartment is 9yrs old. Doesn't occur with washing machine or any other appliance.

I was wondering if I replaced all three bulbs with low watt energy saving bulbs that it may work as a workaround.

Any advice greatly appreciated.

regards.

BarryD

No idea, but normally lights and power sockets should be on separate circuits and therefore not affect each other. Sounds like these lights may be wired into the same circuit that delivers power to the socket that your dishwasher is plugged into. Were the lights added in after the build maybe as a DIY project?

That said, my knowledge of wiring is limited to ordinary houses, not apartment blocks!!

Par1

pippip wrote: »

Hi all,

Just wondering could anyone help.

Basically our apartment kitchen has three downlights (Gu10 50w) When all three bulbs are in and the dishwasher is turned on the lights go very dim. If I take a bulb out the remaining two stay at full brightness.

I know it may be hard to tell without testing things but what would peoples best guess be thats causing the problem. Apartment is 9yrs old. Doesn't occur with washing machine or any other appliance.

I was wondering if I replaced all three bulbs with low watt energy saving bulbs that it may work as a workaround.

Any advice greatly appreciated.

regards.

Your issue seems to be with the mains feeding your apartment. Factors such as distance from meter, sub board distribution (and amount) are the main factors. The lights are dimming because of the load demand within your apartment and from other apartments. If the dimming problem is constant then its more than likely the mains which you should get checked as a loose neutral connection also gives that symptom especially as different circuits are creating one issue.

If its a mains issue i.e size and distance then thats a little more problematic and you may find theres not a lot of options as your problem is then down to supply factor/Diversity setup from provider.

pippip

Cheers lads,

Its all original build <Mod edilt: no company names please> we purchased from new 8/9 yrs ago, nothing adjusted since. Its been rented out the last two and that seems to be when this started as we never had an issue when we lived there.

Hopefully if its a mains issue the problem might be the management company's to fix. I'll have a look at the switch board and see if I can kill the power to lights and dishwasher separately, if I can would that definitely be the mains then?

Would it by any chance just be a fault in the dishwasher? or would that just blow the switch and being a separate circuit still shouldn't effect the lights?

2011

Par1 wrote: »

Your issue seems to be with the mains feeding your apartment. Factors such as distance from meter, sub board distribution (and amount) are the main factors. The lights are dimming because of the load demand within your apartment and from other apartments. If the dimming problem is constant then its more than likely the mains which you should get checked as a loose neutral connection also gives that symptom especially as different circuits are creating one issue.

If its a mains issue i.e size and distance then thats a little more problematic and you may find theres not a lot of options as your problem is then down to supply factor/Diversity setup from provider.

Just to add:
The problem could also be that the cable supplying the distribution board (fuse board) may be undersized. Switching on the dishwasher increases the overall load to the appartment causing an increase in current. The increased current causes an increased volt drop.

In other words the lights may be getting 230V before you siwtch the dishwasher on. Once this load is added the lights may only get 200V causing them to dim. This volt drop is proportional to the load. The volt drop can be reduced by having a larger cable supplying the distribution board.

Larger cables cost more and this appartment was built at the peak of Celtic tiger

BarryD

Did you have the same dishwasher and light set up when you first lived there at which there was no problem? Curious that problem only arises when dishwasher is used and not when washing machine is run. Both potentially heat water and therefore use more power in that phase, though one unit might take in a hot water supply. Do you have a hot water immersion or is the water heated by gas boiler? or supplied from a central boiler for all aparts? If you do, does the lighting problem occur when this is in use?

Basically what I understand from the lads above is they are suggesting that the combined power draw from your dishwasher and lights is causing a voltage drop due to deficiencies in the mains supply to the apartment. If you wanted to rule out a problem with the dishwasher, have it off but turn on every other electrical appliance you have (kettles and air heaters use a good bit of juice) and see if problem still arises with lights. If it doesn't, then you'd suspect the dishwasher. There have been a few publicity campaigns running recently regarding a known fault in certain dishwashers - we had ours fixed free a few months back.

pippip

Thanks lads, Yes all the same appliances as when I lived there. Never replaced anything yet, will look into any recalls of the appliances.

Hard to test as not living there now. Tenants only mentioned it was the dishwasher. I remember I used to have everything going at once when i lived there no problem at all. Its only the three downlights in the kitchen. The three in the bathroom are fine. The rest of the apartment have energy saving bulbs and no issue with dimming there either.

Apartment has immersion, which we never used, hot water was always from our own gas boiler central heating. I'm in between tenants this week so when I'm out next I'll test plugging loads of things in and see what happens.

I know its not ideal but would the low watt energy bulbs help or am I misunderstanding the issue, I've never been good at understanding electrical workings and voltage etc.

Par1

2011 wrote: »

Just to add:
The problem could also be that the cable supplying the distribution board (fuse board) may be undersized. Switching on the dishwasher increases the overall load to the appartment causing an increase in current. The increased current causes an increased volt drop.

In other words the lights may be getting 230V before you switch the dishwasher on. Once this load is added the lights may only get 200V causing them to dim. This volt drop is proportional to the load. The volt drop can be reduced by having a larger cable supplying the distribution board.

Larger cables cost more and this apartment was built at the peak of Celtic tiger

Thats it true - I mentioned that in post but probably didn't state mains size as i assumed the place is tested and certified accordingly. 2011 is right in what he says and i agree. I would get your mains checked first to eliminate that. As 2011 says volt drop could be an issue but its more likely a current issue as he said also - fuse discrimination may be another factor. If the mains cables from MDB to SDB's are not sized accordingly then they may be fused at a lower rating to protect cables however this will become apparent during periods of increased demand (fuses will heat - thermally trip).

You also have to keep in mind that all installations have a diversity factor which assumes that everyone will not be using maximum rating all at once. In a simple installation if we switched on every light and utilised every socket outlet to its potential output then our main individual fuses would trip on O/L.....enter diversity !

BarryD

If you suspect the dishwasher, check it sooner rather than later. I think the problem with ours, a Bosch, was in the control panel and a potential fire hazard. It had actually malfunctioned a couple of times and tripped the ELCB, though it worked on. So no harm to check the ELCB in your consumer unit when you're at it - there's generally a test button beside it. You'd want that to be working for safety reasons.

ted1

Take 135w off the load and stick in 3 5W LEDs.

pippip

ted1 wrote: »

Take 135w off the load and stick in 3 5W LEDs.

That was actually my exact plan. Should it work?

The fact that when I take the third bulb out, dropping 50w, and the other two become fully bright I thought this may be a solution.
I know it wouldn't be ideal and its always best to find the problem but money is tight at the moment and really was hoping for a workaround. I found an article with serial numbers for the recalled dishwashers so going to check this anyway.

I was actually in Homebase at the weekend and typically they were packed in two's, so looking at €30 altogether, which led me to see if anyone could confirm my theory before i bought them.

Par1

pippip wrote: »

That was actually my exact plan. Should it work?

The fact that when I take the third bulb out, dropping 50w, and the other two become fully bright I thought this may be a solution.
I know it wouldn't be ideal and its always best to find the problem but money is tight at the moment and really was hoping for a workaround. I found an article with serial numbers for the recalled dishwashers so going to check this anyway.

I was actually in Homebase at the weekend and typically they were packed in two's, so looking at €30 altogether, which led me to see if anyone could confirm my theory before i bought them.

The LED's may be sensitive to volt drop (if it is a volt drop). Is the dimming light only refined to the kitchen ceiling light, have you noticed? Does the kitchen ceiling lights dim under any other condition. If possible can you plug the dishwasher in and look for the power neon to illuminate so you know the dishwasher has supply then flick off the 20 amp MCB's at the fuseboard one at a time then reset as you go (2 people are needed for this). When you get to the MCB which you know is powering the dishwasher turn on the kitchen ceiling light. Whilst kitchen ceiling light is on trip the dishwasher MCB and observe - the kitchen ceiling light should remain on while dishwasher neon goes off. This will indicate if both are on separate circuits. It would be bizarre if they are linked, i assume there is no sub board in the kitchen (small fuse board) and we are talking about the ceiling mounted down lights as opposed to undercounter mounted down lights ??

pippip

I'll try and test all that when I'm out there next.

No separate fuse board, they are all wired into a combined light-switch panel on the kitchen wall.
Main lights, undercounter lights (not installed), oven, dishwasher, washing machine, extractor fan.

As I said has been rented out and tenants only reported the kitchen lights diming with dishwasher.

2011

pippip wrote: »

I'll try and test all that when I'm out there next.

No separate fuse board, they are all wired into a combined light-switch panel on the kitchen wall.
Main lights, undercounter lights (not installed), oven, dishwasher, washing machine, extractor fan.

Please clarify what you mean by a "combined light-switch panel".
This might help explain your problem.

Par1

pippip wrote: »

I'll try and test all that when I'm out there next.

No separate fuse board, they are all wired into a combined light-switch panel on the kitchen wall.
Main lights, undercounter lights (not installed), oven, dishwasher, washing machine, extractor fan.

As I said has been rented out and tenants only reported the kitchen lights diming with dishwasher.

Grand well when you get a chance to investigate then put your findings on here and we can then advise a little bit more....best of luck!

pippip

2011 wrote: »

Please clarify what you mean by a "combined light-switch panel".
This might help explain your problem.

Basically this but each item's name is engraved above each switch and its three over three (not three beside three).



I also found a bad image of the fuseboard. I have adjusted it slightly to try and make it clearer.

Par1

Can you recall what names are engraved on the plate i.e lights only or Dish washer Wash machine Ext Fan etc....are the 2 switches seperate switches 3 over 3 or one big combined plate 3 over 3?

pippip

Sorry, its exactly this but with switches installed. If i remember rightly the switches are:

Main Lights
Counter lights
Washing machine
Dishwasher
Extractor fan
Oven

Par1

pippip wrote: »

Sorry, its exactly this but with switches installed. If i remember rightly the switches are:

Main Lights
Counter lights
Washing machine
Dishwasher
Extractor fan
Oven




Ahha that puts things into perspective. Thats called a grid switch, it could be a simple feed or neutral issue within that grid switch which would make sense id check that first and see how many feeds are within that grid (your electrician can do that). What sort of oven/cooker do you have is it electric or gas?

pippip

Gas hob, electric oven. Not sure if the hob igniters clicks when oven switch is off. They arent an all in one appliance.

Par1

pippip wrote: »

Gas hob, electric oven. Not sure if the hob igniters clicks when oven switch is off. They arent an all in one appliance.

Ok ask your electrician to check out the oven/hob supply while he is there. The fuse in the distribution board seems to be a 20 amp which may need attention depending on load required/setup.

The grid switch will reveal everything once he has a look at that. Hopefully its a simple solution and you get sorted soon.

Let us know what the outcome is anyway.

pippip

Cheers, will get someone out and report back. Thanks for the help, I always like getting some sort of idea of where the problem may be and an understanding of it all before sending someone in.

Par1

pippip wrote: »

Cheers, will get someone out and report back. Thanks for the help, I always like getting some sort of idea of where the problem may be and an understanding of it all before sending someone in.

Your welcome and good thinking!!

2011

pippip wrote: »

Sorry, its exactly this but with switches installed. If i remember rightly the switches are:

Main Lights
Counter lights
Washing machine
Dishwasher
Extractor fan
Oven

This is an unusual setup, definitely not standard practice.

It suggests that the dishwasher might be fed from the same circuit as the kitchen lights (which is not ideal).
If this is the case it would explain why the lights are dimming.