Discuss Changing original 32Amp contactors for solid state relays? in the Electric Underfloor Heating Wiring area at ElectriciansForums.net

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ABB ESB40-40-230AC/DC - https://new.abb.com/products/GHE3491102R0006/esb40-40-230ac-dc-installation-contactor

The ABB contactor is a good make and well suited. It is a silent or hum-free design and the 40A AC1 (resistive and low inductance or PF nearly 1) rating for the contacts is excellent for your application.

I don't know what the Uruguay electrical regulations stipulate for switching to countenance single pole switching. At the moment all your contactors are used for double pole switching; this is certainly necessary for those UFH elements wired across L1 and L2 but for those across L1-N and L2-N single pole may be allowed - I just don't know. However, double pole is to be preferred because it maintains uniformity of wiring scheme for the UFH system and there is some advantage in splitting the arc across two pairs of contacts when they open to prolong life. I would not opt for single pole switching.

The aforesaid means that to continue with double pole switching you would need to obtain a 6 pole contactor if you wanted one to switch three sets of heating elements in the way a showed in my last diagram. Such a contactor I is rarer than 4 pole and thus I expect pricier. I don't know if you can obtain a silent 6 pole contactor.

Using one contactor to switch 2 or more UFH zones has two drawbacks; if it fails you have lost all heating and when it closes or opens the large current change will cause a noticeable and perhaps troublesome voltage transient in your home and maybe to your neighbours. Far better to sub-divide the load switching over 3 contactors to reduce the magnitude of each transient step. Already I notice that you have quite a variation in supply voltage as loads in your home are powered on and off which indicates a higher supply impedance than is typical in the UK. Switching the UFH zones as one will be noticeable and annoying.

Which leads on to the idea of switching each zone directly using a wifi 'contactor'. In theory this is possible but great care is needed to ensure the power contacts have an adequate AC1 rating and can cope with frequent switching during the day. I'd have to see the specification to comment further. Would it be silent? Would I do it in 'one step'? - no, because I like my functionality appropriately realised in the best possible way. I speak from an industrial background so in the domestic setting one might be more inclined to economy of components.

Sorry about the rather long-winded reply - I have nothing else to do.

:)
 
ABB ESB40-40-230AC/DC - https://new.abb.com/products/GHE3491102R0006/esb40-40-230ac-dc-installation-contactor

The ABB contactor is a good make and well suited. It is a silent or hum-free design and the 40A AC1 (resistive and low inductance or PF nearly 1) rating for the contacts is excellent for your application.

I don't know what the Uruguay electrical regulations stipulate for switching to countenance single pole switching. At the moment all your contactors are used for double pole switching; this is certainly necessary for those UFH elements wired across L1 and L2 but for those across L1-N and L2-N single pole may be allowed - I just don't know. However, double pole is to be preferred because it maintains uniformity of wiring scheme for the UFH system and there is some advantage in splitting the arc across two pairs of contacts when they open to prolong life. I would not opt for single pole switching.

The aforesaid means that to continue with double pole switching you would need to obtain a 6 pole contactor if you wanted one to switch three sets of heating elements in the way a showed in my last diagram. Such a contactor I is rarer than 4 pole and thus I expect pricier. I don't know if you can obtain a silent 6 pole contactor.

Using one contactor to switch 2 or more UFH zones has two drawbacks; if it fails you have lost all heating and when it closes or opens the large current change will cause a noticeable and perhaps troublesome voltage transient in your home and maybe to your neighbours. Far better to sub-divide the load switching over 3 contactors to reduce the magnitude of each transient step. Already I notice that you have quite a variation in supply voltage as loads in your home are powered on and off which indicates a higher supply impedance than is typical in the UK. Switching the UFH zones as one will be noticeable and annoying.

Which leads on to the idea of switching each zone directly using a wifi 'contactor'. In theory this is possible but great care is needed to ensure the power contacts have an adequate AC1 rating and can cope with frequent switching during the day. I'd have to see the specification to comment further. Would it be silent? Would I do it in 'one step'? - no, because I like my functionality appropriately realised in the best possible way. I speak from an industrial background so in the domestic setting one might be more inclined to economy of components.

Sorry about the rather long-winded reply - I have nothing else to do.

:)
Many thanks for the full write up.
I'll look for 3 abb contactors following your advice.
Now the upstairs box is a right mess and I want to tidy it up.
Looks like we have 1 contactor for 4 zones. 4 live cables going out but one neutral for each 2 live cables. Live cables on terminals 2 and 3(2 coming out of each). I'll need to draw this out as looking at the mess it's impossible to see. I traced which wires go to which ufh last night as I want to control my office ufh independently.
 

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As you are the father, spouse and breadwinner please take heed of this: If you are going to be putting your fingers in among the wiring you must invest in an approved voltage indicator in order to prove dead once you have de-energised and isolated. A digital voltmeter or a neon screwdriver are not reliable. You do not need to spend much. I have a DILOG because they are good value for money and I rarely do any work these days preferring to employ an electrician for anything major.

ISOPK2 | Di-LOG - https://www.dilog.co.uk/product/isopk2/

Time spent discovering how things have been wired is well spent - do not assume anything.
 
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As you are the father, spouse and breadwinner please take heed of this: If you are going to be putting your fingers in among the wiring you must invest in an approved voltage indicator in order to prove dead once you have de-energised and isolated. A digital voltmeter or a neon screwdriver are not reliable. You do not need to spend much. I have a DILOG because they are good value for money and I rarely do any work these days preferring to employ an electrician for anything major.

ISOPK2 | Di-LOG - https://www.dilog.co.uk/product/isopk2/

Time spent discovering how things have been wired is well spent - do not assume anything.
Thanks for the link of suggested equipment Marconi. Sound advice.

I've done a sketch of how I believe 2 of the rooms are wired up upstairs. From one of the 4 pole outlets they have 2 live wires going to each room. Just one blue neutral though on series. I would like to have these 2 controlled rooms controlled independently. Not sure how that would be achieved without installing a new digital thermostat on the wall. Would like to have them cabled independently like I do downstairs with the double pole contactors or something similar. They only draw about 1000w each.
 

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Good morning. Re #44. Could you measure the voltage between earth and the red and then the blue on the supply side of the contactor to establish their potential please. I suspect they are connected to L1 and L2.
 
Did you spot the danger in the wiring shown in your picture in #42? You will have to sleeve the red conductor or shorten it. Until then keep your fingers out!

The zone you mention is fed across L-N and I am pretty sure L2-N because your L2 is higher voltage than your L1 in previous readings.

You will need two double pole contactors each supplied by the same L-N pair as now.

Each of the elements is then fed by a double pole output from one or the other contactor.

Alas, you will have to run in a new neutral to the point where the elements' Ns are joined - but you expected the requirement to do that. It was lazy wiring not to run one in the first place. Use the same thickness cable as now.

You can then think about one of these wireless thermostats and receivers for each element such as these:

Honeywell RF DT92E1000 Wireless Digital Room Thermostat | ElectricalDirect - https://www.electricaldirect.co.uk/product/honeywell-rf-dt92e1000-wireless-digital-room-thermostat-611235?vat=1&shopping=true&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQP_fehCHwVa2GQkvKOaTv03u74WSe2iyqTlWLn4Ehsbqn3kHMTNCMcaAqTsEALw_wcB

Or a programmable wireless thermostat like this one:

2 in 1 Programmable Wireless Room Thermostat - 22874 - Controls | BES.co.uk - https://www.bes.co.uk/2-in-1-programmable-wireless-room-thermostat-22874
 
Did you spot the danger in the wiring shown in your picture in #42? You will have to sleeve the red conductor or shorten it. Until then keep your fingers out!

The zone you mention is fed across L-N and I am pretty sure L2-N because your L2 is higher voltage than your L1 in previous readings.

You will need two double pole contactors each supplied by the same L-N pair as now.

Each of the elements is then fed by a double pole output from one or the other contactor.

Alas, you will have to run in a new neutral to the point where the elements' Ns are joined - but you expected the requirement to do that. It was lazy wiring not to run one in the first place. Use the same thickness cable as now.

You can then think about one of these wireless thermostats and receivers for each element such as these:

Honeywell RF DT92E1000 Wireless Digital Room Thermostat | ElectricalDirect - https://www.electricaldirect.co.uk/product/honeywell-rf-dt92e1000-wireless-digital-room-thermostat-611235?vat=1&shopping=true&gclid=Cj0KCQjwhZr1BRCLARIsALjRVQP_fehCHwVa2GQkvKOaTv03u74WSe2iyqTlWLn4Ehsbqn3kHMTNCMcaAqTsEALw_wcB

Or a programmable wireless thermostat like this one:

2 in 1 Programmable Wireless Room Thermostat - 22874 - Controls | BES.co.uk - https://www.bes.co.uk/2-in-1-programmable-wireless-room-thermostat-22874

Thanks Marconi. If you feel the urge a diagram would be very helpful thanks.

Yes looks like the 2 other zones have the same set up. (using the 1st and 2nd poles each going to 2 zones). 6 zones in total from the 3 poles.

btw that black tape on the red cable is just holding the 3 wires in a bundle don't worry no connections under the insulating tape. Looks like they ran out of cable ties!! A lot of laziness in this set up.
 
Hi Marconi,

Hope this works as I've been unable to upload any more photos which is odd. Maybe a limitation on my account? Used an image sharing site for these.
Think I will need to draw a diagram as its such a mess in here. Put some tape around a couple of cables just to label them

Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
 
I'll get a drawing to you later once I have a moment to remove the plastic panel cover to check again. In the meantime I've set up a nice automation server on a docker. Some scripting with the sensors and works brilliantly. So many options here.

Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
 
Hi Marconi.

I believe this is how they have wired it. 2 of the UFH zones are tiny (1m2) bathrooms so use very little. Not 100% on the middle UFH but looks like they share the same cables.

Changing original 32Amp contactors for solid state relays? {filename} | ElectriciansForums.net
 
Hello. What I cannot gauge from the photos is how much space is available on the DIN rail to clip on new double pole contactors. The space available for the new ones determines how many separately controlled zones can be configured. Could you have a gander and tell me please?
 
If I remove the old timer on the left and move the cbs to the left I have about 22/23 cm to play with. Would like to have the one power meter in there (about 1cm wide) measuring all the kWh used by all the combined UFH zones. Good up to 40amps.

I'd be happy if I could just separate the last 2 UFH zones on the right.

Many thanks
 
A standard DIN module is 17.5mm wide. So with two power meters that is 35mm - one for L1 and one for L2. Which leaves 220-35 = 185mm

A double pole 20A ABB contactor is a standard DIN module -the spec says 18mm. So you could fit in up to 10 of them.

ABB ESB20-20N-01 - https://new.abb.com/products/1SBE121111R0120/esb20-20n-01-installation-contactor

Could you have a think about how you want the zones arranged knowing that you have room for circa 12 standard DIN modules - and do you want a power meter for each zone?
 

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