Welding socket needed for 17th edition board?

[Ruggers]

I'm going to purchase a welder of 150 amps, until I have it I don't know much about how much power it will draw from the mains but I don't want it tripping out the garage and extension circuit breaker/MCB or whatever they are called now.

It is a 17th edition 16 way board and I'm sure it either has a spare way or 2 places left that aren't linked to the split board if that makes sense.

I'm just wondering if it's worth putting an extra socket direct from the board to the garage for the welder only to prevent damage to my ring main 2.5mm cable and tripping it?

 

[EFLImpudence]

What kind of plug is fitted to the welder?

 

[westie101]

Do NOT connect one of them to any supply without the permission of your DNO which is Electricity NorthWest. Tel 08001954141
To do so can risk your supply being disconnected

Please read this: -

http://www.enwl.co.uk/docs/default-...nce-for-interference-with-supply.pdf?sfvrsn=5

INTERFERENCE WITH SUPPLY TO OTHER CUSTOMERS
INTRODUCTION
The purpose of this Electrolink is to give general guidance to customers concerning possible interference with the supply to other customers.

Experience has shown that certain electrical equipment may give rise to voltage disturbances that affect the supply to premises of other customers and cause conditions that interfere with the proper use of the electricity supply.
The rights of customers are protected by Regulations and provide in extreme cases for the disconnection of a customer,whose use of electrical equipment or of the electricity network connection causes
interference with the supply to other customers. Fortunately, such action is rarely taken but it may become necessary to require the modification or disconnection of the equipment giving rise to interference.

TYPE OF INTERFERENCE
1. Voltage Fluctuations

Sudden voltage changes (due, for example, to the starting of electric motors or the control of heating loads by burst-firing of thyristors) may cause lighting systems to “flicker” in an annoying manner. The degree of annoyance depends on the magnitude of the voltage change and the frequency of occurrence.
Voltage depressions of less than 0.5% may cause complaints if the repetition rate is about 10 times per second. However, where the cause of the voltage depressions is infrequent (ie occurs at intervals of more than 2 hours) then depressions of up to 3% in voltage may be acceptable.


2. Harmonics

Non-linear loads (eg thyristor controls involving “chopping” of the 50Hz waveform by variation of the firing angle) can produce significant harmonics of the fundamental waveform. These may interfere with communication circuits, sensitive electronic equipment and may cause damage to power factor correction capacitors. Sub-harmonic frequencies can sometimes be generated and these may cause particular difficulty.

3. Voltage Unbalance

Single-phase and other unbalanced loads may cause the three-phase electricity distribution network to become unbalanced. Unbalance in excess of 2% may cause overheating of electric motors. Normallyunbalance of the supplyat 33kV and 132kV is restricted to less than 1.0% and at lower voltages to less than 1.3%.


4. Voltage Transients

Switching, especially of inductive loads, can generate voltage transients (“spikes”) with magnitudes of several hundred volts and durations of fractions of a microsecond. These can disrupt the operation of computers and other digital equipment. Reference should be made to the Electrolink No7 “Computers and Mains Electricity Supply”.

5. Communications Signals

A number of devices are now available which use the custom
er’s internal wiring as a communication path. These are
not approved for communication between premises by means of
Electricity North West’s elec
tricity distribution network
and the customer should ensure that the signals fr
om such devices are confined to his installation.


ADVICE CONCERNING SOME TYPES OF EQUIPMENT

1. Electric Welders

An application for connection for welding purposes should state clearly the type, rating and supply voltage of the welding equipment before any arrangement is made for its installation. The connection of welding equipment is subject to the following factors that will be taken into account on receipt of an Application form.

(a) Welders for connection between phase and neutral lines (
nominally 230V) can be accepted for ratings only of
5kVA and below.

(b) Welders above 5kVA rating where the connection to the customer is not at high voltage should be connected between phases of the three-phase supply (nominally 400V).

(c) Provision should be made for the correction of the power fact or of the installation, which, because of the
connection of welding equipment, may be unduly low.


The foregoing factors are applicable to most parts of Electricity North West’s electricity distribution network but there may be special cases where even these factors will be subject to modification.
(d) Welders, such as resistance types, having high ratings may require a supply delivered to the premises at high voltage and are the subject of special negotiations with Electricity North West for each individual case

And before there are any comments about adherence to Regulations, if it was your lights flickering I'm sure that you would want something done about it.

 

[JohnW2]

Do NOT connect one of them to any supply without the permission of your DNO which is Electricity NorthWest. Tel 08001954141 ... To do so can risk your supply being disconnected.

If permission is sought (which I imagine that it rarely is) to use a plug-in DIY welder, is that permission ever not granted - and, if so, how does the DNO decide which cases to allow and which not to allow?

Kind Regards, John

 

[westie101]

If permission is sought (which I imagine that it rarely is) to use a plug-in DIY welder, is that permission ever not granted - and, if so, how does the DNO decide which cases to allow and which not to allow?

Welders frequently get refused in many situations

By calculation of the system impedance to the "point of common coupling"* and the effect that the initial inrush current (which is usually higher than the 7x of a direct on-line motor) will have on the voltage at that point.

If it is excess of that permitted permission will be refused without any network modifications which the applicant would have to pay for.

The initial calculations and advice are free of charge

* a common point where other customers are connected, so in the case of a single phase underground supply this would be the joint where the service cable connects to the main.
Yes that means that if the customer using the welder gets flickering lights they have caused their own problem and only they can cure it!

 

[westie101]

Perhaps as an example, as a trainee I was asked to look at an application for a huge amount of spot welding load for a proposed factory producing radiator on the outskirts of Blackpool.

Calculation showed that the only way to avoid interference with other customers was to use two 6.6kV cables in parallel from the 6.6kV busbars of a 33/6.6kV substation (so the PCC was those busbars) which was about a mile from the proposed site
The factory was never built!

 

[JohnW2]

Perhaps as an example, as a trainee I was asked to look at an application for a huge amount of spot welding load for a proposed factory producing radiator on the outskirts of Blackpool. ... Calculation showed that the only way to avoid interference with other customers was to use two 6.6kV cables in parallel from the 6.6kV busbars of a 33/6.6kV substation (so the PCC was those busbars) which was about a mile from the proposed site!

That makes sense for a "huge amount of spot welding load". I suppose what I was really asking is how common it is for the impedance of your network to be sufficiently high that a small 'portable', 'plug-in' DIY welder would produce problems of voltage variations ('interference with other customers').

Kind Regards, John

 

[Ruggers]

Thanks for all advice but can we stick to my question please rather than escalate into the usual forum arguments people can get carried away with.
All good advice will be considered.

The welders I'm looking at normally say they draw around 16amp max if i remember correctly and I won't be using it for any long cycles. I have a friend locally who uses his with no problems, I just want to be over cautions and make sure no damage occurs to my wiring as I don't plan on moving home and don't want to do re wires in the near future.

 

[westie101]

I suppose what I was really asking is how common it is for the impedance of your network to be sufficiently high that a small 'portable', 'plug-in' DIY welder would produce problems of voltage variations.

To be honest I have no idea as these applications are dealt with at Preston which is about 110 miles from my base

 

[JohnW2]

Thanks for all advice but can we stick to my question please rather than escalate into the usual forum arguments people can get carried away with. All good advice will be considered. ... The welders I'm looking at normally say they draw around 16amp max if i remember correctly and I won't be using it for any long cycles. I have a friend locally who uses his with no problems, I just want to be over cautions and make sure no damage occurs to my wiring as I don't plan on moving home and don't want to do re wires in the near future.

As has been said, the one thing which is clear (which probably comes within the scope of 'being over-cautious') is that you contract with your electricity supplier will require you to get permission before using any welding equipment, connected to whatever circuit.

It is not the running current, nor the duration of use, which is the issue - as westie has said, it's the initial 'inrush' current which causes all the problems. Your house wiring is not likely to be at risk but, as above, there are other issues.

Kind Regards, John

 

[westie101]

The welders I'm looking at normally say they draw around 16amp max if i remember correctly and I won't be using it for any long cycles.

It's the short cycle welding that causes the problem, if I recall we would expect an inrush current of 9x everytime a weld is struck, that will drop to 1x as the weld progresses.
So everytime you strike an arc the instantaneous current could be up to 144amps
Your wiring and circuits could cope with this but that level of current can cause your neighbour's lights to dip under certain conditions.
It is this situation that the DNO must avoid.

As the time between each strike of a weld will be under 2 hours the permitted dip visible to others will be 0.5% i.e 1.15 volts, in fact if the welding piece is not perfectly clean the arc will be constantly striking and breaking.
So as your mate has one, do his lights dip a bit? Do his neighbours dip a bit?

Did he get permission? If not is he aware of the risks?

 

[EFLImpudence]

You will have to research the manual for whichever welder you decide to buy.

If it comes with a 13A plug then you will be able to plug it in to a normal socket.

The welders I'm looking at normally say they draw around 16amp max

Then it will be necessary to have a dedicated circuit and suitable socket and plug.

1. Electric Welders

An application for connection for welding purposes should state clearly the type, rating and supply voltage of the welding equipment before any arrangement is made for its installation. The connection of welding equipment is subject to the following factors that will be taken into account on receipt of an Application form.

(a) Welders for connection between phase and neutral lines (nominally 230V) can be accepted for ratings only of
5kVA and below.

if i remember correctly and I won't be using it for any long cycles. I have a friend locally who uses his with no problems, I just want to be over cautions and make sure no damage occurs to my wiring as I don't plan on moving home and don't want to do re wires in the near future.

As above.

 

[JohnW2]

If it comes with a 13A plug then you will be able to plug it in to a normal socket.

The welders I'm looking at normally say they draw around 16amp max

Then it will be necessary to have a dedicated circuit and suitable socket and plug.

Indeed - and, as I said, either way, the house wiring would not be at risk. However, that is clearly a different matter from that of potential problems ('to other customers') due to inrush currents.

1. Electric Welders .... the following factors that will be taken into account on receipt of an Application form. ... (a) Welders for connection between phase and neutral lines (nominally 230V) can be accepted for ratings only of 5kVA and below.

I presume you're not (I would say mistakenly) taking that to mean that welders ≤5kW are necessarily always acceptable to the DNO?

Kind Regards, John

 

[ban-all-sheds]

I read it as saying that single-phase welders >5kVA will not even be considered.

 

[westie101]

I presume you're not (I would say mistakenly) taking that to mean that welders ≤5kW are necessarily always acceptable to the DNO?

John W2 is correct, it does not mean that a welder of that size is acceptable, only that a 5kVA is the highest we would permit on a single phase supply