Discuss hottub in the Electrical Forum area at ElectriciansForums.net

uHeat Banner - Forum Discount Available
This official sponsor may provide discounts for members

Midwest

-
Esteemed
Arms
I would not; its not really safe to have a permanent or semi permanent extension lead, outside running appliances.
 

Spoon

-
Mentor
Esteemed
Arms
Welcome to the forum mate.
I would not recommend running an extension lead to the shed for something that is going to be used for a long time, like a small fridge. Also extension leads have a max rating of 13A. I'm presuming the power requirements of your small fridge and hot tub will be more than this.
Does your socket supply have RCD protection?
 

pc1966

Esteemed
Arms
Supporter
If your hot tub is 3kW (13A) then it is already at the limit for a socket so you could not use the fridge as well as when the compressor is on they typically takes or the order of 5A or so.

Yourt best choice is to get an electrician to put in a double socket in the shed (and probably some lights when they are at it). That would need a viable cable route from house to shed to either bury armour cable, or a route around above ground where it can safely be clipped to walls / fences / etc.
 
If your hot tub is 3kW (13A) then it is already at the limit for a socket so you could not use the fridge as well as when the compressor is on they typically takes or the order of 5A or so.

Yourt best choice is to get an electrician to put in a double socket in the shed (and probably some lights when they are at it). That would need a viable cable route from house to shed to either bury armour cable, or a route around above ground where it can safely be clipped to walls / fences / etc.
ok ive been told from a engineer at work that i could put a rcd in the house socket then run a 16amp lead 2.5mm to my shed said should be ok?
 
Welcome to the forum mate.
I would not recommend running an extension lead to the shed for something that is going to be used for a long time, like a small fridge. Also extension leads have a max rating of 13A. I'm presuming the power requirements of your small fridge and hot tub will be more than this.
Does your socket supply have RCD protection?
going to put a rcd in house socket hot tub has one fitted
 

Midwest

-
Esteemed
Arms
What sort of ‘lead’ are you intending to use?

When I use an extension lead, to cut my grass for example, it’s used under my supervision, and inspected before and after use.

As said, using an extension as a permanent supply, is not a good design. The cable could become easily damaged, without you being aware.

You should have a properly designed circuit and suitable cable. I would suggest installed by a competent electrician. A poorly designed installation, especially in an outdoor environment could be very dangerous.
 

pc1966

Esteemed
Arms
Supporter
  1. ok ive been told from a engineer at work that i could put a rcd in the house socket then run a 16amp lead 2.5mm to my shed said should be ok?
Almost, but there are issues to consider:
  • You really ought to have RCD protection on your house sockets anyway, so it would be worth checking your CU (consumer unit = fuse box) to see if it has it or not (or post a photo here).
  • Having an out-building off your socket ring circuit is not ideal, as if you have a fault outside you trip off your house sockets as well. You may be OK with that, or have an isolator switch fitted to allow it to be turned off independently if there is a fault, but having a dedicated circuit from your CU is the recommended approach.
  • The type of cable uses (and how it is run) has to be suitable for the outdoor environment. So the usual flat twin & earth is not acceptable unless run in some form of conduit, for example. You would need to look at either SWA (steel wire armoured) if there is any mechanical risk of damage, or NYY-J (like SWA but without the armour), or H07RN-F (flexible rubber that is UV tolerant) if the cable is safe in duct or run up high away from likely impact from garden activities.
  • The size of the cable (2.5mm, 4mm, etc) depends on the length as well as the load current. Since it is not just the current carrying capacity (i.e. overheating risk) that has to be considered, but also the voltage drop under load.
  • If you have extraneous metal stuff in the shed (unlikely, but in case...) such as metal water pipes, or it is a steel framed building, then you need to have the earth bonded. Depending on the type of your supply (i.e. if it is TN-C-S which is the most common type these days) that can either require a large earth conductor (e.g. 10mm) or steps to have an isolated earthing arrangement (known as TT).
  • As you are based in England & Wales, this sort of work probably comes under Part P of the building regulations and needs notification to the local authority.
Getting in a professional electrician who is registered with on of the "competent person schemes" is by far the easiest route to this.
 
Last edited:
What sort of ‘lead’ are you intending to use?

When I use an extension lead, to cut my grass for example, it’s used under my supervision, and inspected before and after use.

As said, using an extension as a permanent supply, is not a good design. The cable could become easily damaged, without you being aware.

You should have a properly designed circuit and suitable cable. I would suggest installed by a competent electrician. A poorly designed installation, especially in an outdoor environment could be very dangerous.
i was thinking the sort they use for camping 16amp with the 3 pins
 
Almost, but there are issues to consider:
  • You really ought to have RCD protection on your house sockets anyway, so it would be worth checking your CU (consumer unit = fuse box) to see if it has it or not (or post a photo here).
  • Having an out-building off your socket ring circuit is not ideal, as if you have a fault outside you trip off your house sockets as well. You may be OK with that, or have an isolator switch fitted to allow it to be turned off independently if there is a fault, but having a dedicated circuit from your CU is the recommended approach.
  • The type of cable uses (and how it is run) has to be suitable for the outdoor environment. So the usual flat twin & earth is not acceptable unless run in some form of conduit, for example. You would need to look at either SWA (steel wire armoured) if there is any mechanical risk of damage, or NYY-J (like SWA but without the armour), or H07RN-F (flexible rubber that is UV tolerant) if the cable is safe in duct or run up high away from likely impact from garden activities.
  • The size of the cable (2.5mm, 4mm, etc) depends on the length as well as the load current. Since it is not just the current carrying capacity (i.e. overheating risk) that has to be considered, but also the voltage drop under load.
  • If you have extraneous metal stuff in the shed (unlikely, but in case...) such as metal water pipes, or it is a steel framed building, then you need to have the earth bonded. Depending on the type of your supply (i.e. if it is TN-C-S which is the most common type these days) that can either require a large earth conductor (e.g. 10mm) or steps to have an isolated earthing arrangement (known as TT).
  • As you are based in England & Wales, this sort of work probably comes under Part P of the building regulations and needs notification to the local authority.
Getting in a professional electrician who is registered with on of the "competent person schemes" is by far the easiest route to this.
i was goin to use 16 amp 1.5 cable like the cables for camping as its not going to be on 24/7 just when tub is in use
 

telectrix

-
Mentor
Esteemed
Arms
i was goin to use 16 amp 1.5 cable like the cables for camping as its not going to be on 24/7 just when tub is in use
you should leave the hot tub on 24/7 durung the times you want to use it. from cold it will take a day and a hlf to heat up. no use switching it on and sitting around for 36 hours waiting.
 

UNG

-
Mentor
Esteemed
Arms
So you come on here for advice and then go to
ok ive been told from a engineer at work that i could put a rcd in the house socket then run a 16amp lead 2.5mm to my shed said should be ok?
then you finally decide on
i was goin to use 16 amp 1.5 cable like the cables for camping as its not going to be on 24/7 just when tub is in use
why bother asking
From the past experience of customers I've seen the mess some of these tubs make of long 1.5mm² extension leads running at their maximum for 30 or more hours

Have you any idea how long it takes a cold tub to become a hot tub, on average you are looking at a temperature rise of about 1°C / hour so you are probably looking at 30-40 hours before it gets to temperature to help it along you could always boil a few hundred kettles
 

Reply to hottub in the Electrical Forum area at ElectriciansForums.net

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
Top