How wire storage heaters

JOHNPT

Hi can anyone tell me how to wire storage heaters. What is the most common way its done. I know there is dual tariff meter which charges cheaper rate at night but where is the time clock located to turn on the storage heaters at night. Is it in the consumer unit or is it beside each storage heater? Also why are contactors used? Why cant you bring a supply from top of MCB feeding each storage heater to a timer beside each storage heater?
Also when there is dual metering is there always two seperate consumer units? If there is dual metering does the consumer need a seperate timer or is the timer not provided by the ESB. Is contactors needed and what are there purpose.
If u find that a storage heater dosent work how can u test them during the day as there is no electricity going to them so how do u know if it is the supply that is at fault or the storage heater?

I really appreciate any help any advice with the above. I know its a long question.

fishdog

where is the time clock located to turn on the storage heaters at night

This is in the meter cabinet and supplied and sealed by the ESB. They provide you with dry contacts that you can use to energise the coil of a contactor that brings on your storage heaters.

Why cant you bring a supply from top of MCB feeding each storage heater to a timer beside each storage heater?

You could, but you would need a timer per heater then and the timer would have to be rated for the current of its corresponding heater or have more contactors! Would look crap and be expensive and over complicated.

Also when there is dual metering is there always two seperate consumer units?

No, just 1 with a doulble switch fuse.

Is contactors needed and what are there purpose.

Yes. A contactor with several poles is required. One pole for each heater that will operate on night rate.

If u find that a storage heater dosent work how can u test them during the day as there is no electricity going to them so how do u know if it is the supply that is at fault or the storage heater?

Simple, apply 230 volts across the coil of the contactor.

JOHNPT, if I was doing this job I would simply buy a consumer unit that is already made up for you for storage heating. Devi make these, and Eurosales, Kellihers etc. sell them. There is a connection drawing with this unit also.

I hope this helps.

To be honest, this is work that should be done by a qualified electrician. I am sure you have a good understanding of what is going on, but more than that is required to do something like this, it is not DIY stuff.

Good luck with it.

JOHNPT

Thanks for reply. Im an appren electrician just want to find out more information about how wire or test storage heaters. Is that any site where there is circuit diagrams. how do you apply 230 volts across coil of contactor. Would really appreciate more detail and information. Fas dont do it and didnt do storage heaters in work. A detailed way of how it is wired I would be very grateful. Thanks in advance

davelerave

with dual tariff metering and a few storage heaters (up to 8kw) seperate fuseboards and double pole switches don't come into the equation as there's only the one supply.
as far as the timing goes for dual tariff you would use the esb timing for blunt instruments like storage heating or you can do your own timing where required for electric agas and heat pumps etc.
the easiest way to test the heaters is to energise the contactor and use a clamp meter or feel them for heat

fishdog

Im an appren electrician just want to find out more information about how wire or test storage heaters

Fair enough

how do you apply 230 volts across coil of contactor

On the base of the contactor there are 2 terminals marked "A1" and "A2".
Connect A2 to the main neutral bar with a 1.5 cable and connect A1 to the top of an MCB supplying a lighting circuit (normally a 10A MCB). This should energise the contactor. You will hear it click on. Turn this MCB on and off and the contactor should switch on and off.

JOHNPT

Really appreciate reply. Beginning to make sense now. So basically the ESB timer when it switches on at 11 pm enegises the contactor on fuse board which supplies power to storage heater? Right? So does the contactor energise the storage heater directly or does it energise the MCB. Wat is the proper order in wiring. Thanks again

davelerave

a multipole contactor like a 4pole 20amp would be after mcbs,a larger 2 or 3 pole would be before mcbs

JOHNPT

Whats the most frequent way. Say u had a house with 3 storage heaters being newly built wat way would the wiring be done. Dual tariff meter or dual metering. If it is dual metering is there a seperate consumer unit just for the storage heaters? Thanks for all replies

davelerave

if u had electric water heating or a similar additional off peak load youd get dual tariff the boards can be done seperate or combined with seperate nsh metering

fishdog

So basically the ESB timer when it switches on at 11 pm enegises the contactor on fuse board which supplies power to storage heater? Right?

Exactly

So does the contactor energise the storage heater directly

Yes. The contactor is between the MCB and the storage heater. This is why it is multipole i.e. 2,4 or 8 pole.

If it is dual metering is there a seperate consumer unit just for the storage heaters?

No.

I think you are assumng that there are 2 supply cables from the ESB meters, there is only 1. This goes to 1 consumer unit that has everything in it. This can be bought as a single item already made up. It is very simple then.

JOHNPT are you in Kevin street at the moment??

JOHNPT

So the most common is dual tariff one cosumer unit? I still not sure what way they are wired. Can someone explain exactly the wiring circuit for dual metering and dual tariff. In wat order is the timer. Is it ESB or consumer timer. Are contactors used on both systems? Thanks

fishdog

PM sent JOHNPT

JOHNPT

Thanks fishdog your reply seems to make sense. Not in Kevin street will be in few months. But I still dont get it does the esb timer just energise the contactors feeding the storage heaters? There is just one contactor which does a few storage heaters? What is the MCB used for then or is there a seperate MCB for each storage heater? So there is a seperate feed from esb timer to contactor anD then from the contactors are the supply cable to the storage heaters? And all this is in one consumer unit? Really appreciate help

davelerave

i assume by dual metering u mean seperate meters try and look up a few drawings.seperate nsh metering can switch the load direct but u need a contactor to incorporate controls