Replacing Electric Wall Heater Wire

[JohnW2]

Could be a pilot wire supply from a central programmer or room stat. Dimplex do a heating system like this.

The web site shows the Stiebel Eltron CAEC 750 as a straight panel heater. My guess is that the 5 panel heaters may, at some time, have been storage radiators and these have been swopped out for panel heaters at some time. ... That may be the reason for the "two supplies" label if that heater location had a storage rad with a boost convector feature.

I've so far not found instructions for the CAEC 750, but have found those for the CAES 750, which may be very similar. That is double insulated, requiring a 3-core cable:

Phase: brown
Neutral : blue wire
Control wire: black wire
....
Programming by control wire
Our convectors can be connected to any of the programming devices (timer or programming unit) in accordance with the diagram of Figures 5 and 6. The control wire is connected to provide central programming of operation in the comfort and economy operating modes and, where included in the unit, "protection against frost". In units in which the control wire is not connected to a programming device, for reasons of safety it is vital to insulate the black wire and in no case connect it to a grounding wire (green-yellow).

This can only safely be determined by a site inspection.

Indeed, but the precise arrangement of the circuits (or CU) does not necessarily have to be known (provided everything in the CU is switched off prior to any work) in relation to the OP's desire to ensure that the cable join/extension is safe.

Kind Regards, John

 

[JohnW2]

I've so far not found instructions for the CAEC 750, but have found those for the CAES 750, which may be very similar.....

The CAEC and CAES panel heaters both have the same super-slim design and both can be used as part of a Chrono pass controlled heating zone if linked by a pilot wire.
The CAEC incorporates two thermostats; one for the 'Comfort' temperature setting and the other for the 'Economy' set-back temperature setting. The CAEC will accept the Chrono pass slot-in controller and is therefore suitable for use as a 'master' within the heating zone.
The CAES incorporates a single electronic thermostat and can be used either as a controlled 'slave' within a zone or as a stand-alone heater with no programming facility. If used within a Chrono pass controlled zone, the 'Economy' set-back temperature is pre-set at 3.5 degrees below the full 'Comfort' setting.
The very accurate and sensitive electronic thermostats in these heaters ensure that room temperatures are precisely controlled.

Kind Regards, John

 

[deadshort]

Hi, i would be concerned about a 750w heater on a 16a mcb ?

Unless i'm mistaken that's a switch and not a FCU ? its connected to


Kind regards,

DS

 

[flameport]

Under the tape is wire extension device. This doesn't look that safe hence looking to improve it.

The simplest solution: http://www.tlc-direct.co.uk/Products/BG458.html

 

[Taylortwocities]

Hi, i would be concerned about a 750w heater on a 16a mcb ?

The MCB is there to protect the fixed wiring. Most storage radiators I have seen (of all sizes) have a DP switch, not an FCU as the isolation device.

 

[deadshort]

Hi, this is a panel heater rated at 750w what size of fuse would you put in the plug of an appliance rated at 750w ?

Kind regards,

DS

 

[dmuk]

Thanks for all the responses.

I am pretty certain these panel heaters were installed when the property was built. The property was built around 7/8 years. It seems the safest is to turn everything off prior to doing any work.

I haven't tried to remove the panel from the wall, but I can see the following setup:

1) Heater in photo:
Heater > Wire > Join > Wire > Join > Wall

2) Other heaters:
Heater > Wire > Wall

Below are some closer photos of the wires. It seems that it may well be easier just to cover up the (taped) join with something more. It seems unlikely I will be able to install one clean wire from heater to wall.

Wall:
View media item 83444
Wire to Join:
View media item 83445

 

[EFLImpudence]

Hi, this is a panel heater rated at 750w what size of fuse would you put in the plug of an appliance rated at 750w ?

As said, it depends on the cable.

What size fuse would you use for a 40W lamp?

 

[deadshort]

3A

Kind regards,

DS

 

[JohnW2]

Hi, this is a panel heater rated at 750w what size of fuse would you put in the plug of an appliance rated at 750w ?

As said, it depends on the cable. ... What size fuse would you use for a 40W lamp?

3A

A 3A fuse has an In approximately 17 times the current taken by a 40W lamp. A 16A MCB has an In of only about 5 times the current taken by a 750W heater. What is your problem with the latter if you are happy with the former?

As has been said, the OPD is there to protect the cable, regardless of the load. People regularly install cooker circuits protected by 32A MCBs, but it's not uncommon for the load to only be a <13A oven - do you have a problem with that?

Kind Regards, John

 

[JohnW2]

Below are some closer photos of the wires. It seems that it may well be easier just to cover up the (taped) join with something more. It seems unlikely I will be able to install one clean wire from heater to wall.
Wall:View media item 83444Wire to Join: View media item 83445

I'm a bit confused here. The first picture is obviously the one to the switch, with brown, blue and black cores (which would be consistent with what the instructions say about the cable from the heater). However, the second picture shows blue/brown/yellow-green conductors - is that the cable coming from the heater (which seems inconsistent with the instructions), or are there, in fact, two joins in the cable between heater and switch?

Kind Regards, John

 

[deadshort]

Hi, this is a panel heater rated at 750w what size of fuse would you put in the plug of an appliance rated at 750w ?

As said, it depends on the cable. ... What size fuse would you use for a 40W lamp?

3A

A 3A fuse has an In approximately 17 times the current taken by a 40W lamp. A 16A MCB has an In of only about 5 times the current taken by a 750W heater. What is your problem with the latter if you are happy with the former?

As has been said, the OPD is there to protect the cable, regardless of the load. People regularly install cooker circuits protected by 32A MCBs, but it's not uncommon for the load to only be a <13A oven - do you have a problem with that?

Kind Regards, John

No. As this has been deemed aceptable complies with the regs, and more importantly my insurance company will pay out if it burns my house down.
The manufacturers instructions require the heater is 'hardwired to a switched spur'.

Kind regards,

DS

 

[JohnW2]

No. As this has been deemed aceptable complies with the regs, and more importantly my insurance company will pay out if it burns my house down. The manufacturers instructions require the heater is 'hardwired to a switched spur'.

Ah, you must have found some instructions which I failed to find - can you provide a link? The ones I could find (albeit for the CAES 750) do not say that. The nearest to anything relevant they say is ....

The installation must comply with applicable standards. The installation must not comprise a multiple-pole breaker device the contact opening gap of which is less than 3 mm

Kind Regards, John

 

[deadshort]

Sorry, must not comprise ?

Kind Regards,

DS

 

[deadshort]

Hi, this is a panel heater rated at 750w what size of fuse would you put in the plug of an appliance rated at 750w ?

As said, it depends on the cable.

So, if i wire my bedside lamp(40w) using 2.5mm twin and earth what size of fuse would you fit in the plug and if higher than 3A why ?

Thanks,

DS