Electric panel heaters..??

[sparkyjohn1]

I recently had another spark ring me up , about a job i completed late last year.Ranting that I havn't installed the heating circuit correctly, and i should re-visit to property to correct it.

The property didn't have a gas supply, so was asked to supply and Install a heating solution. ( electric rads / heaters etc.)

I have included a picture. ##best schematic diagram i could do on microsoft paint.##

This is how i did the job,, please tell me if you can find anything wrong with it..

Only thing i can think of is that the IN-LINE STAT, maybe borderline regarding max current draw,,,rated 16amp. but that is about it.. everything else seems o.k,??

Please let me know if you have any feedback..
thanks

 

[Octopus]

What did he say is wrong?

 

[sparkyjohn1]

I don't know,, just asked me to go round, meet him on site, to discuss snags,,, the heating being one of them,, amongst other petty things.
My guess is he thinks the stat aint 'man enough' as most stats are not rated at 16 amps.. I had to search high and low for that one.... especially being an 'in-line' one most are remote, or wired through contactors, it was the best way i could think of doing it per the clients request,,. Also please note , that the heaters were going to be 2Kw at the start, with no stat,(individually controlled) (thats why the 6mm was used as main feed ).. and 10 amp breakers, downstream. but I made a calc of volume of the rooms they were feeding and 1Kw seemed more of a feasible solution..

 

[monkeyelectric]

I don't know,, just asked me to go round, meet him on site, to discuss snags,,, the heating being one of them,, amongst other petty things.
My guess is he thinks the stat aint 'man enough' as most stats are not rated at 16 amps.. I had to search high and low for that one.... especially being an 'in-line' one most are remote, or wired through contactors, it was the best way i could think of doing it per the clients request,,. Also please note , that the heaters were going to be 2Kw at the start, with no stat,(individually controlled) (thats why the 6mm was used as main feed ).. and 10 amp breakers, downstream. but I made a calc of volume of the rooms they were feeding and 1Kw seemed more of a feasible solution..

Its probably because the breaker to supply all the heaters is 40amp which then runs through a 16amp stat

 

[tazz]

Too right, the only protection this 16a stat has, is a 40amp mcb, you should have used a contactor

 

[londonlec]

I would have fed a contactor from that timer, even though it is rated for the load.

 

[sparkyjohn1]

yeah, i realise this,, but the stat was an after thought,,, after the heaters were downgraded to 1 Kw,,I had already wired. it for the 2Kw models.. the wiring and the breakers involved are all 'over compensating ' the max current draw, and the stat is equal to max current draw if you take 1Kw x 4 = 4kW.. roughly equates to 16 amp.?! I do realise the confusion the M.C.B may have caused but everything seems o'k AND electrically safe to me..

 

[tazz]

I would power the timeswitch off a 6a mcb or lower, and use a contactor off the 40a mcb to supply 2nd cu

 

[MDJ]

you can buy 20 amp stats, change the breaker to 20 amp as well and your done, however a contactor would have been the way to do the job.

 

[monkeyelectric]

yeah, i realise this,, but the stat was an after thought,,, after the heaters were downgraded to 1 Kw,,I had already wired. it for the 2Kw models.. the wiring and the breakers involved are all 'over compensating ' the max current draw, and the stat is equal to max current draw if you take 1Kw x 4 = 4kW.. roughly equates to 16 amp.?! I do realise the confusion the M.C.B may have caused but everything seems o'k AND electrically safe to me..

What would happen should they replace the panel heaters with 2kW heaters then your stat would melt!

 

[sparkyjohn1]

how about I just change the main M.C.B for a 16 AMP one.? not one for cutting corners, as I'd thought i'd covered all areas, but would that cure the situation,,,? then maybe changing the M.C.B'S Downstream too?? maybe 6 amp? each,?

 

[wozz]

1kW? how small are these rooms?

Slight overload on stat, and stats dont always switch what they say they can.

Congrats on terminating 6mm in a stat.

How is the 6mm installed?

 

[MDJ]

how about I just change the main M.C.B for a 16 AMP one.? not one for cutting corners, as I'd thought i'd covered all areas, but would that cure the situation,,,? then maybe changing the M.C.B'S Downstream too?? maybe 6 amp? each,?

4kw at 230 volt ? 16 amp? stick a 20 in and be done with it, however if you added a contactor in to the supply from the main db to the small db, you could have the stat control the coil.

 

[sparkyjohn1]

I'll search for a 20 amp in line stat... and go with the comment above MDJ

 

[wozz]

What would happen should they replace the panel heaters with 2kW heaters then your stat would melt!

same can be said for almost anything, 7671 doesnt mean you have to futureproof installations for incompetence.

 

[atm84]

Surely the client should be contacting you. Not the electrician. He didn't order the work. As a professional he should advise the client and then its up to the client to request you to go back.

 

[tazz]

There are 4 different rooms....yet on stat...?.....why dont you put 16a stat/timers in each room, so the temperature can be controlled in each room....better for Temp control and sorts out your problem.

 

[MDJ]

the whole job is wrong Tazz, however he will be doing the minimum he has to, I bet the electrician who has asked him to attend site has some ideas which may suprise him lol

 

[monkeyelectric]

same can be said for almost anything, 7671 doesnt mean you have to futureproof installations for incompetence.

No but you still have to install switchgear correctly rated for the ocpd!

 

[sparkyjohn1]

The client wanted 1 communal stat to control the 4 electric heaters from 1 position,,, As i've already said, it was an after-thought by the client, so wasn't wired accordingly,,. I'll be honest with you guys.. I've been a domestic spark all my life, proper house- basher, not fully conversant with contactors and the like...... a bit old school.. (only ever installed M.C.B's on the DIN rail... no timers, contactors., bell trannies,,, etc... )... sorry if i come across a bit of a one trick pony,,, just something i've never really done before...

 

[wozz]

No but you still have to install switchgear correctly rated for the ocpd!

I think sizing it to the load would be better.

 

[tazz]

The client wanted 1 communal stat to control the 4 electric heaters from 1 position,,, As i've already said, it was an after-thought by the client, so wasn't wired accordingly,,. I'll be honest with you guys.. I've been a domestic spark all my life, proper house- basher, not fully conversant with contactors and the like...... a bit old school.. (only ever installed M.C.B's on the DIN rail... no timers, contactors., bell trannies,,, etc... )... sorry if i come across a bit of a one trick pony,,, just something i've never really done before...

Din rail is a god send imo.....you can add din rail contactor, timers, delay timers, PSU,current control....the gear is endless these days, and makes the job so much neater and professional.

 

[wozz]

the whole job is wrong Tazz, however he will be doing the minimum he has to, I bet the electrician who has asked him to attend site has some ideas which may suprise him lol

Whilst it may not appear a usual design to say its wrong on the info given is a bit much, i wouldnt want to have to walk into a room and turn a heater on, i certainly dont do that at home! also these are fairly low consumption heaters not masses of money being thrown away, depending on how rooms are used, also there may have been budget restrictions which did not allow for a more controllable system.

Of course you could be correct, depending on what the customer asked for and how much money they were spending, the design wouldnt be my first suggestion but it may well be a suggestion further down the line.

 

[MDJ]

Whilst it may not appear a usual design to say its wrong on the info given is a bit much, i wouldnt want to have to walk into a room and turn a heater on, i certainly dont do that at home! also these are fairly low consumption heaters not masses of money being thrown away, depending on how rooms are used, also there may have been budget restrictions which did not allow for a more controllable system.

Of course you could be correct, depending on what the customer asked for and how much money they were spending, the design wouldnt be my first suggestion but it may well be a suggestion further down the line.

But it is wrong, he has a potential 40 amp supply running through a 16 amp stat, what is right about that ??

 

[sparkyjohn1]

thanks Tazz, I will bear the DIN rail comment in mind,,,, maybe its because i dont have long left before retirement i am reluctant to to learn and expand my expertise,,,, although, i do feel that i'm being left being with all the the new technology these days... it baffles me sometimes....
Thank you for you kind comments,, i will take them on board.,

 

[sparkyjohn1]

the supply isn't 40 AMP..!!!

 

[tazz]

A standard £8-£10 room stat....or a £25 stat/7 programmer from a local shed, installed in each room would certainly not break the customers bank

 

[sparkyjohn1]

YEAH, its a 40 amp m.c.b,, but the max current draw is only 16 amp...!!!

 

[tazz]

thanks Tazz, I will bear the DIN rail comment in mind,,,, maybe its because i dont have long left before retirement i am reluctant to to learn and expand my expertise,,,, although, i do feel that i'm being left being with all the the new technology these days... it baffles me sometimes....
Thank you for you kind comments,, i will take them on board.,

Some of use here are on our last 5-10 years....but keeping up is the only way to survive my friend....its a hard world

 

[monkeyelectric]

I think sizing it to the load would be better.

For this particular circuit i would still rather see it configured differently or downrate the ocpd to suit!

 

[MDJ]

YEAH, its a 40 amp m.c.b,, but the max current draw is only 16 amp...!!!

I get your point, however is it 16 amp? 4.3 amps per kilowatt on 230 volts lol, anyhow I have mentioned the way to do the job with a contactor etc, I understand your view regarding an after thought by the customer.

 

[sparkyjohn1]

right ,,, last comment of the night,,, before i get too wound up about things,,
which one of you sparks out there would accept the circuit that i've installed as being safe ( tho not entirely orthadox.).. and which ones of you think that it is dangerous and needs to be altered??

 

[wozz]

But it is wrong, he has a potential 40 amp supply running through a 16 amp stat, what is right about that ??

How is 40A going to get pulled through the stat?

 

[MDJ]

not dangerous john

 

[tazz]

I get your point, however is it 16 amp? 4.3 amps per kilowatt on 230 volts lol, anyhow I have mentioned the way to do the job with a contactor etc, I understand your view regarding an after thought by the customer.

Which also raises MDJ question previously....why not install a 20a mcb...?

 

[sparkyjohn1]

And its actually 245 volts , (quite close to sub station,) not being picky or anything....

 

[sparkyjohn1]

thanks MDJ, really appreciate it...

 

[Badged01]

Not unsafe!. We can be finiky over what the total load is but its close enough for hard cash to 16A (diversity?) and whilst you could argue the 40A C/B is irrelevant as the characteristics of the loads mean its unlikely to carry overload current beyond the stat rating (assuming fault protection is covered) but maybe a 20A would give some piece of mind to someone if you wanted to make a change!

 

[tazz]

Not unsafe!. We can be finiky over what the total load is but its close enough for hard cash to 16A (diversity?) and whilst you could argue the 40A C/B is irrelevant as the characteristics of the loads mean its unlikely to carry overload current beyond the stat rating (assuming fault protection is covered) but maybe a 20A would give some piece of mind to someone if you wanted to make a change!

just the stat melting....before the 40a mcb trips.....but hey nevermind

 

[Badged01]

just the stat melting....before the 40a mcb trips.....but hey nevermind

But thats the whole point, its unlikely to see an overload current likely to melt it by the exact nature of the loads! (Fault current may be a different thing but Im assuming the RCD and installation method reduce the fault risk to a minimum).

Sections 433 and 434 expand on the rationale.