Wiring dilemma

[mainline]

A bit of a dilemma / argument with the way the Project manager, who has supplied me with a wiring diagram that he's done for control of hot water in a block of 4 cottages.

The cottages are pme earthing, there are 2 phases split between the 4 cottages.

There needs to be a call for heat from 2 cottages which are on a different phase to the boiler, his wiring brings the supply in to a wiring centre to supply the zone valves / and tank stats.

There are 2 immersion tanks, one downstairs and one up, both zone valves are in the same location with a cable for the downstairs stat tank having to run through the house to the upstairs one.

He is adamant that i wire it the way he wants, he's installed 2 5 core cables to the wiring centre from the cottage to the wiring centre which there is totally no need to do as it only requires the call for heat to the boiler.

Wiring it his way will mean that both the tank stats, zone valves etc will all have a supply + phase on them from another location.


The prospect of not being able to isolate this wiring centre valves/stats both up and downstairs, i can't see as being right when either a no volt 2 channel programmer would do a far better job with a lot less wiring and would mean that everything apart from a single connection would be from the same supply.

There is a bit more thrown into the mix as one of the cottages has to use a wireless switch to be able to turn off the bio mass hot water. He's provided one with an SL output which is totally useless as that SL would have to be wired from the other supply along with the earth and neutral from the other location.

I'm thinking on Monday to refuse to do this, am I right in doing so ?

Thoughts, questions ?

 

[Tim Howard]

I'm on the same page as you.
Doing it his way....
1 - multiple phases within an enclosure, 400v label.
2 - everything would need to be plastered with warning notices about how to isolate and work on this system.
3 - the occupant can't safely isolate things in their property
4 - the poor chap changing a zone valve or a cylinder stat isn't going to expect the supply to come from another place.


There is a an RF-solutions product for wirelessly sending a switched live a long way, which I've used in the past when a builder thought it was a combi
and cut a load of wires. (There's even a two way one designed for pump over-run).

I'd be seriously temped to adopt the idea that the wiring centre is supplied locally, the zone valves are supplied locally, and the boiler fire is wireless, meaning everything can be turned off as expected.

 

[mainline]

It could be done simply by using a contactor on the call for heat along with an isolator, the rest would then be on the local supply.

The stats on the immersion tanks are open back things where you can see the bimetal strip stats are only held on by the sprung wire.

These are holiday cottages, and it was only the other day that he gave me 14 pages of eicrs with loads of c2s from 5 yrs ago because he forgot !!.

 

[Tim Howard]

It could be done simply by using a contactor on the call for heat along with an isolator, the rest would then be on the local supply.

I missed there was cable run already, it's a no brainer to me to do it that way.

I think the principle to keep in mind, however it's done, is there need to be means of isolation under the control of anyone working on it.
Doing it his way this becomes silly and complicated, e.g. a lockable isolator the boiler end, or a 4 pole isolator where it comes into the cottage!

You could point out that accessing the boiler property to work on another one will inconvenience guests in the future.

Your way it just works..

 

[mainline]

I missed there was cable run already, it's a no brainer to me to do it that way.

I think the principle to keep in mind, however it's done, is there need to be means of isolation under the control of anyone working on it.
Doing it his way this becomes silly and complicated, e.g. a lockable isolator the boiler end, or a 4 pole isolator where it comes into the cottage!

You could point out that accessing the boiler property to work on another one will inconvenience guests in the future.

You way it does itself, even if the contactor coil gets energised you turn the whole lot off with one FCU as everyone would expect and nothing would pass through the contactor.

We had an argument about it, and he stormed off, saying "just do it the way I've told you" I said you can do it as I'm going home.
2 mins later he came back in full apologetic.

I started to wire it but realised he wanted another switch in the CU to turn the other valve off for when it's not being used.

And a wireless switch in the other cottage to do the same thing.

These are needed because he didn't get a 2 channel programmer, so it's not able to time the hot water or turn it off. (He said we don't need a timer) but we need to be able to turn if off with a switch in the CU next to the Immersion one, hence another run of cable upstairs to the wiring centre.

The point is, do you think I'm right in refusing to do it his way.

 

[Tim Howard]

The point is do you think i'm right in refusing to do it.

If he can't be reasoned with and it comes down to an ultimatum of 'just make it work my way' then yes I'd walk away.
If he lets you add suitable means of isolation to make it safe then I'd begrudgingly accept that.

(at that point it's work arguing that less isolation is needed your way for comparable costs)

 

[mainline]

If he can't be reasoned with and it comes down to an ultimatum of 'just make it work my way' then yes I'd walk away.
If he lets you add suitable means of isolation to make it safe then I'd begrudgingly accept that.

(at that point it's work arguing that less isolation is needed your way for comparable costs)

I am of the opinion that doing it his way just creates too much of a risk.

But can't think of anything in the Regs to say it can't be done his way.

Bear in mind they are not just another supply but also another phase which is going to 2 zone valves, 2 tanks, and 2 switches in other locations.

The N L E of the other supply is also being brought into the wiring centre from the other location.

 

[Tim Howard]

But can't think of anything in the Regs to say it can't be done his way.

My wife has just stuck an Agatha Christie thing on, so I will gladly grab the regs book and have a think
Isolation, multiple phases, multiple sources of supply, and linking earthing systems are all possible areas of interest.

 

[Bruspark]

Run each switch/ thermostat to 12V double insulated power supplies and cable from the outputs to the boiler room Diode each (low voltage isolated, non grounded CE) supply cable together for extra points and connect it to a Mains rated relay by the boiler. If the cables are long use a 13.6v PSU in each location to avoid thick cables
Note of explanation at each end of the cables. Done

 

[Tim Howard]

Am I right the wiring centre would only have the other supply in it, coming from the boiler?
I'm as not concerned about the different phase per se. after all we are used to finding multiple phases behind a light switch in commercial buildings.

For me it's all about isolation, and the fact it simple isn't how anyone would expect it to work.
My considered view is that I think it would comply if there was adequate warning notices at consumer unit, by wiring centre and zone valves, and at both immersion tanks, and an isolation point before the wiring centre.

Some regs that I think are pertinent:

132.15.201 Effective means, suitably placed for ready operation, shall be provided so that all voltage may be
cut off from every installation, from every circuit thereof and from all equipment, as may be necessary to prevent
or remove danger.

134.1.7 Where necessary for safety purposes, suitable warning signs and/or notices shall be provided.

514.11 Warning notice: isolation
514.11.1 A warning notice of such durable material as to be likely to remain easily legible throughout the life
of the installation shall be fixed in each position where there are live parts which are not capable of being isolated
by a single device. The location of each disconnector (isolator) shall be indicated unless there is no possibility of
confusion.

514.15.1 Where an installation includes alternative or additional sources of supply, warning notices shall be
affixed at the following locations in the installation:
(i) At the origin of the installation
(ii) At the meter position, if remote from the origin
(iii) At the consumer unit or distribution board to which the alternative or additional sources are connected
(iv) At all points of isolation of all sources of supply.

 

[mainline]

Am I right the wiring centre would only have the other supply in it, coming from the boiler?
I'm as not concerned about the different phase per se. after all we are used to finding multiple phases behind a light switch in commercial buildings.

For me it's all about isolation, and the fact it simple isn't how anyone would expect it to work.
My considered view is that I think it would comply if there was adequate warning notices at consumer unit, by wiring centre and zone valves, and at both immersion tanks, and an isolation point before the wiring centre.

Yes, there would only be the supply from the other location in the centre.

Some regs that I think are pertinent:

132.15.201 Effective means, suitably placed for ready operation, shall be provided so that all voltage may be
cut off from every installation, from every circuit thereof and from all equipment, as may be necessary to prevent
or remove danger.

134.1.7 Where necessary for safety purposes, suitable warning signs and/or notices shall be provided.

514.11 Warning notice: isolation
514.11.1 A warning notice of such durable material as to be likely to remain easily legible throughout the life
of the installation shall be fixed in each position where there are live parts which are not capable of being isolated
by a single device. The location of each disconnector (isolator) shall be indicated unless there is no possibility of
confusion.

514.15.1 Where an installation includes alternative or additional sources of supply, warning notices shall be
affixed at the following locations in the installation:
(i) At the origin of the installation
(ii) At the meter position, if remote from the origin
(iii) At the consumer unit or distribution board to which the alternative or additional sources are connected
(iv) At all points of isolation of all sources of supply.

Thanks for the effort in having a look, Tim.
It seems to be as I suspected, that there is nothing regs wise that says no.

I've decided that I'm going to refuse to do it anyway, on the grounds that it's going to add needless risks to the installation, especially when there is an easier, cheaper and safer way to do it.

 

[UNG]

While labels or diagrams may suffice now move on a few years when the labels have been painted over or removed for redecoration and not replaced then that is when the problems could occur
Given the project manager / customer has "designed" this control arrangement is he prepared to sign off the design section on the EIC for it, I think that may lead him to rethink his current attitude if he has to take responsibility for it in writing

 

[mort2376]

I would use local contactors that switch feeds to and from the boilers and valves. That way you can isolate the boiler and valves locally with no need for isolation in the separate properties. A simple note on each consumer unit stating that the contactor (if located within the CU) is supplied from XXXXX Isolate ALL supplies before accessing. 415v Labels on units that are on a different phase.

That way the boiler and valves can all be on 1 phase with no issues of introducing multiphase voltages into the control wiring box.

You could even mount the contactors in their own separate housing with <Danger 415v Between Units> labels.

Anything you can do to make it that a plumber expecting 230v on the system to only find that is far better than them making a mistake and somehow cross connecting between 2 phases.

If he is adamant that you do it his way then ask for a written risk assessment which you are going to attached to the certificates as he is going against your professional opinion and therefore he is taking on the risk responsibility by doing that. Or just tell him to Foxtrot Oscar and leave site.

 

[binky]

The point is, do you think I'm right in refusing to do it his way.

absolutely, I have encountered a bodged set of wiring controls which had 3 live inputs from different circuits - firking dangerous!

 

[mainline]

While labels or diagrams may suffice now move on a few years when the labels have been painted over or removed for redecoration and not replaced then that is when the problems could occur
Given the project manager / customer has "designed" this control arrangement is he prepared to sign off the design section on the EIC for it, I think that may lead him to rethink his current attitude if he has to take responsibility for it in writing

He can't sign off, he has very limited knowledge of electrical installations.

 

[mainline]

I would use local contactors that switch feeds to and from the boilers and valves. That way you can isolate the boiler and valves locally with no need for isolation in the separate properties. A simple note on each consumer unit stating that the contactor (if located within the CU) is supplied from XXXXX Isolate ALL supplies before accessing. 415v Labels on units that are on a different phase.

That way the boiler and valves can all be on 1 phase with no issues of introducing multiphase voltages into the control wiring box.

You could even mount the contactors in their own separate housing with <Danger 415v Between Units> labels.

Anything you can do to make it that a plumber expecting 230v on the system to only find that is far better than them making a mistake and somehow cross connecting between 2 phases.

If he is adamant that you do it his way then ask for a written risk assessment which you are going to attached to the certificates as he is going against your professional opinion and therefore he is taking on the risk responsibility by doing that. Or just tell him to Foxtrot Oscar and leave site.

The installation is very easy to make safe, as the 2 calls for heat that are on the same phase pass through the wiring centre. So one contactor + isolator + label would solve the problem, but he's adamant he wants it done his way.

He's exactly the same with the carpenter who's peed off with him telling him how to do things.

Even if it was done his way, I would have to alter the wiring as there is no facility to turn off the hot water.

Another problem is that he's married to the owners' daughter who has shares in the business, the owners are getting on and the husband suffers from short term memory loss.

He came in about 6 yrs ago after losing his job as some marine engineer, over the time he has cost the business thousands and thousands through bad design.

Awkward situation for them.

One major issue for me is that since he's been here, he's given me no reports of issues over the time. I have complained to him that there are issues in these cottages and to have been given satisfactory ones is totally wrong.

2 weeks ago he gave me 14 pages of reports saying that I needed to do remedials as the inspectors have complained that the previous report work from 5 yrs ago hadn't been done.

The cottages have been let out for the last 5 yrs all with unsatisfactory reports.

His excuse was that he forgot.

 

[mainline]

He can't sign off he has very limited knowledge of electrical installations.

I've decided to have a meet with the owners and tell them that I'm refusing to do that part but I am willing to finish off what I've started and then will be leaving for pastures new.

 

[Tim Howard]

I've decided to have a meet with the owners and tell them that I'm refusing to do that part but I am willing to finish off what I've started and then will be leaving for pastures new.

One would like to think that if you told the owners there is an easier, cheaper and safer way to do it then they would support you in that.
I'd also be tempted to say that his method will likely result in someone giving it a C2 in future and you'd end up changing it to the safe way anyway!

 

[UNG]

He can't sign off, he has very limited knowledge of electrical installations.

Just because he has limited electrical knowledge should not stop him from signing the design off on the EIC. When you look at some of the EICR's posted on here and other sites they have clearly been carried out by people with limited electrical knowledge and experience and they still sign them so why should it be different for this guy's design

 

[nicebutdim]

He can't sign off, he has very limited knowledge of electrical installations.

Yet insists on acting as the designer.

I'd walk away, without a second thought.