Confused about rewiring a replacement time lag switch

Salvador3

Hello there,

I wonder if anyone can help with this.

I have a time lag switch to control a power shower. It goes off after 20 minutes. These uses two cables only, no need for a neutral.

The new time lag switch does require a neutral.

The confusion is that I have two neutral joined together not attached to anything, can I use any of the neutral wires or I need to use the neutral that goes to the load (power shower) and if so, how can I tell which of the two it is?

Attaching one picture of the old time slag switch and a picture of the new time slag switch that I found in the reviews of the switch. (Assuming the wiring is correct)

Thanks in advance

mckaymmc0

The new time lag switch is a KH2 model and is rated at 10Amps with a terminal capacity of 1.5mm2.  A power shower is usually 6.5kW or 28 Amps with 10mm2 conductors so this switch couldnt be used as a time delay onload application.

Looking at the size of the cables this doesnt look like the cables supplying the power shower.  Is there a relay or contactor wired into the shower circuit that the time delay switch controls?

Instructions for wiring the time delay switch are online for reference.

FreeBear

mckaymmc0 said:

The new time lag switch is a KH2 model and is rated at 10Amps with a terminal capacity of 1.5mm2.  A power shower is usually 6.5kW or 28 Amps with 10mm2 conductors so this switch couldnt be used as a time delay onload application.

Chinese relays - Wouldn't trust it to switch 5A reliably for any length of time. Certainly not suitable for any shower that has a heating element. However, a power shower is (generally) just a pump using water heated by other means. These are typically wired to a 3A fused supply and consume around 150W max. On that basis, this switch should be OK.

TELLIT01

As a general 'rule of thumb' if you have to ask for advice on a wiring issue, don't do it yourself.  Pay for an electrician to do it.

Risteard

mckaymmc0 said:

The new time lag switch is a KH2 model and is rated at 10Amps with a terminal capacity of 1.5mm2.  A power shower is usually 6.5kW or 28 Amps with 10mm2 conductors so this switch couldnt be used as a time delay onload application.

Looking at the size of the cables this doesnt look like the cables supplying the power shower.  Is there a relay or contactor wired into the shower circuit that the time delay switch controls?

Instructions for wiring the time delay switch are online for reference.

A power shower and electric shower are not the same thing. Also an electric shower won't be 6.5kW - 8.5kW is much more normal. Conductor sizes will depend and may not be 10mm^2.

Ectophile

It looks like the new timer has two neutral terminals - Nin and Nout.  And you have two neutral wires that are currently crimped together.  So cut off the crimp and wire the two neutrals to their respective terminals.

Salvador3

FreeBear said:

mckaymmc0 said:

The new time lag switch is a KH2 model and is rated at 10Amps with a terminal capacity of 1.5mm2.  A power shower is usually 6.5kW or 28 Amps with 10mm2 conductors so this switch couldnt be used as a time delay onload application.

Chinese relays - Wouldn't trust it to switch 5A reliably for any length of time. Certainly not suitable for any shower that has a heating element. However, a power shower is (generally) just a pump using water heated by other means. These are typically wired to a 3A fused supply and consume around 150W max. On that basis, this switch should be OK.

Exactly, the power shower takes hot water from the hot cylinder, there's no heating involved, only a pump. There's a 3amp switch box that controls the power shower. The lag timer sits in between. 

These power showers if run dry for a few seconds would damage the pump hence to prevent people having extra long showers, the lag timer comes in.

Thank you for you comment.

Salvador3

Ectophile said:

It looks like the new timer has two neutral terminals - Nin and Nout.  And you have two neutral wires that are currently crimped together.  So cut off the crimp and wire the two neutrals to their respective terminals.

Thank you so much.

That's more or less what I had in mind.

One live wire to Lin and the other to Lout and the two neutral as you indicated.

Thanks again for your help.