Lights dim on heater start up?

[ipjodan]

Hi all,

My boss has just asked this question in the office to see if any one can answer.

He has a heater in the conservatory (3kw) on start up the lights dim for a very brief time?

What causes this? is there a nice explanation i can give him and get in his good books?

Thanks

 

[RigidRaider]

The problem is that Lancashire employers (I know, I work in Bury) are so notoriously tight fisted and slow to pay their electricity bills that Norweb generally have the voltage turned down a bit. Consequently every time someone switches on a heavy current user, all the lights dim in the building. You should see it here when the boss is torturing the factory lads with the mains cable, the lights flicker worse than Blackpool illuminations on a windy night. Mind you it gets 'em working harder in the factory.

 

[Steve]

hilarious.

its called voltage drop. nothing to worry about. unless the lights nearly go off lol.

 

[HDRW]

its called voltage drop. nothing to worry about. unless the lights nearly go off lol.

In my girlfriend's house in New York (where I am now) it's amazing - just turning on the coffee maker (850W) dims the lights. And when the microwave is running (1.5kW) the voltage on the circuit drops by 9V - and remember there's only 110V to start with!

But then their wiring regulations all seem to be aimed at fire prevention, with little emphasis on shock prevention or voltage drop.

And whereas we introduced ring finals when copper was in short supply, they introduced aluminium wiring, which is what this house has.

Cheers,

Howard

 

[JohnD]

Hooray for Ring Finals!

 

[jj4091]

It can be an indication that the ring main is O/C somewhere.

 

[securespark]

Hooray for Ring Finals!

 

[JohnD]

Hee hee!


Did you like my photo, Secure?

 

[ricicle]

It can be an indication that the ring main is O/C somewhere.

Only if the lights are fed off the ring

 

[Steve]

I remember being in my auntie's new-build house in Canada, a massive house, 5 big bedrooms, double garage, huge kitchen, 3 bathrooms.

Whenever the washing machine was spinning, the hall light would go very dim - about half the light. And this was a new build. This is very common over there. Our electrical system is superior to theirs, IMO.

In the older days of American knob-and-tube wiring, the live and neutrals would be kept as far away from each other as possible, only coming together for fittings! The knobs would be fixed to adjacent joists and run opposite sides of the joist gap. And where they had to come together for an accessory, extra insulation was added. Where wires passed through joists, they'd slip a porcelain tube over it, as if the wire was going to cause the joist to catch fire without it. Still quite a bit of this about, AFAIK. Very well-built stuff though, not like today's American standards, with "wirenuts" and the like

 

[jj4091]

It can be an indication that the ring main is O/C somewhere.

Only if the lights are fed off the ring

Sorry ricicle but you are not correct, I have had this problem at least three times over the last few years. I am not sure why it happens & presume it is the load not being spread around the ring but it is the first thing I check now if someone asks me to look at lights dipping!!!

 

[bernardgreen]

I remember being in my auntie's new-build house in Canada, a massive house, 5 big bedrooms, double garage, huge kitchen, 3 bathrooms.

Whenever the washing machine was spinning, the hall light would go very dim - about half the light. And this was a new build. This is very common over there. Our electrical system is superior to theirs, IMO.

In the 1970's I did some work on equipment interfacing telecoms to radio paging systems in the States and frankly was appalled at the standards of electrical wiring. One equipment room had about 30 outlets with the neutrals all bonded on a sort of ring conductor and with individual radials for the live feeds. I think but cannot be sure (memory fade) that all three phases were shared around the sockets. Changing in to UK type twin and earth radials removed a lot of the noise problems and low volt resets that were plaguing the system

 

[ricicle]

It can be an indication that the ring main is O/C somewhere.

Only if the lights are fed off the ring

Sorry ricicle but you are not correct, I have had this problem at least three times over the last few years. I am not sure why it happens & presume it is the load not being spread around the ring but it is the first thing I check now if someone asks me to look at lights dipping!!!

You're telling me that a break in a ring final would cause another circuit fed from the CU (lights) to dip.I can't see it somehow.Whether there was a break in the ring or not the CU would still see the same load on the ring for a given load.

 

[RF Lighting]

It can be an indication that the ring main is O/C somewhere.

Only if the lights are fed off the ring

Sorry ricicle but you are not correct, I have had this problem at least three times over the last few years. I am not sure why it happens & presume it is the load not being spread around the ring but it is the first thing I check now if someone asks me to look at lights dipping!!!

You're telling me that a break in a ring final would cause another circuit fed from the CU (lights) to dip.I can't see it somehow.Whether there was a break in the ring or not the CU would still see the same load on the ring for a given load.

Not quite.
If the ring has gone O/C then the feed to any given socket will only be fed by one cable instead of two.
The volts drop will increase and as a result so too will the load on the system.

 

[JohnD]

The volts will drop on that leg of that circuit because of the load on its conductors.

But what will happen on other circuits that are fed direct from the CU?
(e.g. a lighting circuit)