Question for experienced heating engineers

[Lee King]

Hello, ive recently passed my core gas and ACS and level 3 apprentiship in plumbing/heating, i have recently applied for a job doing boiler servicing with Southern and Scottish Electricity(SSE) i was told by an operations manager that it would be a good idea to brush up on the electrical side of things.. Basically we did not cover the electrical part as much as i liked to on the collage course and have not been really using what i did learn, with my current employer. So as you can probably guess although i have basic knowledge, i could do with sorting out exactly whats what in my head!

if someone would be kind enough to explain, or if anyone has any notes/tutorials/videos on TESTING:

Resistance to earth
Short circuit
Equipotential bonding

it would be a HUGE help to me.

Thanks alot

LeeKing.

 

[SimonJohns]

Were you ment to be a plumber from birth?

 

[dancinplumba]

get a copy of the 17th edition, this should help..... imo

 

[desrob]

get a copy of the 17th edition, this should help..... imo

are you joking,that will send him over the top.

 

[dancinplumba]

lol i know

 

[Mbear]

Resistance to earth...
Multimeter on ohms and test accross earth and live+switched lives, readings should be over 1mega ohm but most of the time it will be OL

Short circuit checks...
Check neutral to all lives and switched lives, readings should be over about 4ohms

Earth continuity checks....
Test from one earth to all other earths. Readings should be continuity (less than 3/4 ohms)

Polarity...
Mulitimeter on volts.
live to neutral 240v
Live to earth 240v
Neutral to earth 0v

 

[wheeto]

readings should be over about 4ohms

13A is about 20Ω, so your reading on anything other than an immersion should be well over 20Ω.

 

[Noxer]

Digital Multimeter LCD Screen With Test Leads £3.69 free shipping from Kenable at Amazon - HotUKDeals

cheap multimeter mate

 

[Mbear]

My point is anything below 4ish is short circuit.

 

[zzzjim]

Think in terms of earth bonding being good enough to blow 30A trips and fuses . Cheap meters don't realy measure below 1 ohm for a "To Specs test"
( but are less depressing to blow up )

 

[GQuigley67]

SSE are mugs thats all i can say

 

[TipTop]

Sounds like your employer is a big firm so probably need you to demonstrate (quite rightly) safe isolation- Live checks-L-N 240
L-E 0
N-E 0

Then do 'Dead Checks' with resistance to earth either from the block on blr or from case to suitable point i.e earth screw on socket/switch looking for OL

Good Luck

 

[quality]

Think ya got that wrong
L - E should be 240 if it's live

 

[AWheating]

resistance

look at things in the way that can make sense to a plumber.you have a length of 15mm copper supplying a tap with a gate valve in the middle. Now the flow of water being the flow of electricity and the actual volume of water being the current(amps).

If you have the gate valve open giving no resistance to the flow of water then the volume of water to the tap will be very high. (so with electrics the less resistance= more current can pass)

If you have the gate valve half closed giving alot of resistance then the flow of water will be less giving less volume at the tap. (so with electrics the more resistance the less current can pass)


a basic grasp of ohms law will help you alot.

 

[TipTop]

right you are mate!!good typo that!!