Short circuit in home wiring?

[regulaz]

The situation is like this. on one mcb the doorbell is there and on the second the computer point. Both get routed through a RC MCB point which is basically a battery backup point in the store room. when someone presses the bell the lcd display switches off and back on.

what can be done to help this scenario ? replace the bell? ground the doorbell? remove the inverter point?

are these two points somewhat short circuiting ?

 

[regulaz]

would be grateful is some pro member could comment. im a rookie with checking this, but the lcd reacting to the doorbell has to stop.

 

[picbits]

The doorbell could be causing a surge on the system but I've not been able to visualise what kind of electrical system you're using.

A Google search on "RC MCB" sheds no light (pardon the pun)

 

[regulaz]

The doorbell could be causing a surge on the system but I've not been able to visualise what kind of electrical system you're using.

A Google search on "RC MCB" sheds no light (pardon the pun)

its a RCD MCB maybe? 32 amps.

 

[picbits]

So is the RCD (Residual Current Device) tripping ?
Are you using 240V ?
What is the doorbell powered by ? A stepdown transformer or direct to the mains via a switch mode power supply ?

 

[regulaz]

So is the RCD (Residual Current Device) tripping ?
Are you using 240V ?
What is the doorbell powered by ? A stepdown transformer or direct to the mains via a switch mode power supply ?

doorbell direct to mains. it is 240V.

RCD is 2 pole 32 amps, isnt tripping.

 

[picbits]

Do you are possibly getting a voltage droop when the bell is activated.

Why is it connected to the inverter and what kind of inverter are you using ?

What happens if you connect the bell to the mains before the inverter and just use the inverter for the monitor ?

 

[regulaz]

Do you are possibly getting a voltage droop when the bell is activated.

Why is it connected to the inverter and what kind of inverter are you using ?

What happens if you connect the bell to the mains before the inverter and just use the inverter for the monitor ?

the idea was to have the doorbell working just incase of a power outage but that never happened so i connected a voltage regulator in its place even that was unnecessary but it was lying around so i hooked it up for clean power.

i dont have the expertise to switch wires in a panel so ill have an electrician check that out for you if he cant figure it out himself. i can just poke around with a multimeter

 

[KeepItSimpleStupid]

OK, for those folks reading this, I don't think we are dealing with a NORMAL doorbell.

I would first look at the UPS and and see if it's trying to switch to battery mode. Unplug the UPS and FORCE it to operate on battery power and see if the doorbell works. For the initial test, turn off the computer and monitor.

I actually suspect one of two things:
1. The batteries in the UPS are dead especially if they are 5 years or older.
2. The VA rating of the monitor, PC and doorbell exceed the VA rating of the UPS.

Note: VA isn't Watts in this case. The UPS has to handle the surge of all of the bells, not just the operating current. You may have multiple bells on this circuit. The VA load might be 10x the rating of the bell(s).

I wired a bunch of strobes to a Fire Alarm (Actually Hazardous Gas Detection) backup Panel and some didn't work. The PTC fuses were shutting down on the surges. Why only some strobes? The design was changed. Fix: replace the strobes.

It was a little more complicated. Each or some of the strobes ran off a class II limited power supply, so we really didn't want to change that. i.e. run the wiring in conduit and use a separate supply for those strobes.
Suggestions: Check the needed size of the UPS. Buy a UPS with the required VA rating. You MAY be able to add a varistor at each of the bells to limit the surge current. Stage the bells. Wire the emergency system to only operate 1 bell.

I could be off base if RCD means GFCI. Terminology on different sides of the big pond.

 

[dr pepper]

See if you can dig out the supply to the doorbell and disconnect it, and try again, if all is ok then you could temporarily try supplying the doorbell from a plugtop and an extension lead and see if that works.
Theres a possibilty that the mcb itself is iffy, but thats unlikely.

I fairly recently had a phantom doorbell ringer, sometimes in the middle of the night, and sometimes we heard a buzzing sound in the hallway, turned out to be water in the doorbell switch, you might want to check for that.

Also if your doorbell puts mains voltage through the doorbell switch then you really want to change it for a low voltage one before the postman gets zapped.

 

[regulaz]

thanks for the reply guys my bro took away the lcd and im using another lcd which doesnt exhibit this issue . its connected to the same ups, being older draws more power too but doesnt exhibit this issue although im sure the underlying phenomenon is still present since that newer lcd always shows that issue when plugged in. it is a dell s2440L which was showing this.

even a larger crt 21" flat sony trinitron when plugged into the same ups doesnt show this issue. the batteries are relatively new in the UPS.

 

[dr pepper]

At first I'dve thought it was rf noise messing up the lcd, either through the air or through the power lines, however most computer gear now is fairly noise immune so it'd have to be really bad, its not something that vibrating contacts or a pushbutton arc would cause.
Maybe you should just go buy a battery doorbell.

 

[regulaz]

At first I'dve thought it was rf noise messing up the lcd, either through the air or through the power lines, however most computer gear now is fairly noise immune so it'd have to be really bad, its not something that vibrating contacts or a pushbutton arc would cause.
Maybe you should just go buy a battery doorbell.

i think the problem is deeper with the wiring. im trying to figure out what a mess of wiring the electrician made when he was contracted to put in new wiring couple of years ago. ive been mending this rubbish ever since.

the transformer supplying to a 100 odd houses has 10 bus panels installed of which 10 houses are supplied each. when anyone turns on their water pumps it literally wakes me up in my bed. im concerned with all the electromagnetic fields being generated.

this lcd doorbell business is in line with trying to figure out what this mess is about.

 

[dr pepper]

Well then, you'd better take all the covers off, the doorbell and the disboard, and see if you can see where the cables run, shouldnt be too hard, if the 'bell has its own 'breaker, follow the live from the breaker and you'll find the cable that runs out to the push and the 'bell, I spose there could just be a single live going to the push and another single neutral going to the 'bell.
If you pull the main fuse or trip the main breaker then you can use a long wire on a meter with a buzzer to buzz out either ends of the wires.
I know you arent me, however if I was to look at the issue as a job I'd be inclined to chop out the cables for the doorbell and the computer room and fit anew, as I wouldnt want to risk an installation with question marks over it.
Are you in the us with 110, or in the uk or somewhere with 240?
You could threaten the'leccy with reporting them to the electrical governing bodies, but if they've allready botched it then you'll probably only get more of the same.

 

[regulaz]

Well then, you'd better take all the covers off, the doorbell and the disboard, and see if you can see where the cables run, shouldnt be too hard, if the 'bell has its own 'breaker, follow the live from the breaker and you'll find the cable that runs out to the push and the 'bell, I spose there could just be a single live going to the push and another single neutral going to the 'bell.
If you pull the main fuse or trip the main breaker then you can use a long wire on a meter with a buzzer to buzz out either ends of the wires.
I know you arent me, however if I was to look at the issue as a job I'd be inclined to chop out the cables for the doorbell and the computer room and fit anew, as I wouldnt want to risk an installation with question marks over it.
Are you in the us with 110, or in the uk or somewhere with 240?

its 240Volts... i would rewire it all but that would upset my family thinking "oh god there is nothing wrong here, he is just wrecking everything, call the cops" LOL

 

[regulaz]

Well then, you'd better take all the covers off, the doorbell and the disboard, and see if you can see where the cables run, shouldnt be too hard, if the 'bell has its own 'breaker, follow the live from the breaker and you'll find the cable that runs out to the push and the 'bell, I spose there could just be a single live going to the push and another single neutral going to the 'bell.
If you pull the main fuse or trip the main breaker then you can use a long wire on a meter with a buzzer to buzz out either ends of the wires.
I know you arent me, however if I was to look at the issue as a job I'd be inclined to chop out the cables for the doorbell and the computer room and fit anew, as I wouldnt want to risk an installation with question marks over it.
Are you in the us with 110, or in the uk or somewhere with 240?
You could threaten the'leccy with reporting them to the electrical governing bodies, but if they've allready botched it then you'll probably only get more of the same.

ive called over an electrician anything you'd like me to ask him to do esp since that monitor is gone?

 

[regulaz]

the electrician who came visiting did a preliminary check. he said all earth wires from the different rooms at the fusebox panel were joined to a single green earth wire going to the busbar panel but he couldnt locate that wire at the busbar panel. he said rest of the residents also dont have an earth going to their premises from the busbar panel.

there were 3 live and 1 neutral coming from the busbar panel to the fusebox and an earth wire he couldnt locate at the busbar panel but is going from the fusebox alright. he took one 10mm live wire and disconnected it and connected it to the busbar panel frame at one end and the earth wires in the fusebox on the other end.

that did not change the voltage i measured at the light fixtures.

do i have another rookie electrician at my disposal? i think so.. :/

after he left i disconnected the new earth wire (converted from live) at the fusebox from all the earths of the rooms congregating at the fusebox and measured the voltage at light fixtures no change.


question: do i need to locate a separate earth point like the waterpipe? isnt the busbar panel frame good enough for an earth?

 

[regulaz]

after he left i also disconnected the original green earth lead at the fusebox which goes to the busbar panel (which he could not locate at the busbar panel) and put a multimeter from live to that green wire and it showed 235VAC.

seems to be a working earth?

 

[dr pepper]

Sounds like I'd better not get more involved in this, sounds like a can of worms.

It is acceptable in some circles to use a phase wire as an earth, so long as its clearly marked up with sleeving at both ends.

Yes it sounds like your old earth is an earth, a better test would be to use an earth bond meter which tests the connection at a high current.

I dont think I have any more suggestions, only if you think the incomming earth isnt good then that is potentially dangerous.

 

[regulaz]

Sounds like I'd better not get more involved in this, sounds like a can of worms.

It is acceptable in some circles to use a phase wire as an earth, so long as its clearly marked up with sleeving at both ends.

Yes it sounds like your old earth is an earth, a better test would be to use an earth bond meter which tests the connection at a high current.

I dont think I have any more suggestions, only if you think the incomming earth isnt good then that is potentially dangerous.

electricians these days talk more and do less. i could see the earth wire coming from the fusebox to the busbar panel frame clearly. i think he was just trying to look as if he knew something. ( "sir your earth is weak" REALLY!!! )

i've reversed what he did in entirety as it was working fine.

the only solution to voltage at SOME fixtures i can now attribute to internal wiring in specific MCBs, i'll get those checked tomorrow and if nothing works will just run an earth through lighting fixtures and call it a day.

what do you think?