Grounding: + or Neutral?

[Brock]

I was trying to convince my Jazz friend on the benefits of grounding. His speakers recently gave way and was replaced. Car alarm didn't work as well. I told him that it could be due to short circuit due to no grounding in his new Jazz. However, he insisted that there was no need for grounding, and that all new cars already have grounding installed. He went on to quote that his father's car didn't have all these accessories and it still worked fine for so many years. I even copy and paste and emailed him the Grounding Writeup here in MCF. Still, he is not convinced. How to convince?

 

BTW, I'm no salesman!

[Route]

later you see anther thread started by your friend asking how to convince you that grounding doesnt work

 

He went on to quote that his father's car didn't have all these accessories and it still worked fine for so many years.

 

he might be right you know...

[Octopus]

IMHO, I think new cars don't need grounding cos electrical system and wiring should be in good condition. That's why some people said didn't feel any effect after grounding..... But older cars would to a certain extend, benefit from grounding. Just my opinion.

Edited May 9, 2005 by Octopus

[Brock]

Electrical engineers will know. Even HDB block have grounding installed in the event lightning bolt strike. My friend's private terrace house was not grounded and he lost every single electrical equipment at home when his house got 'striked'. Thankfully, he has insurance coverage for all his stuff! I'm pretty sure whether old or new, grounding is a must.

[Apollo]

sorry, the grounding for building (lightning conductor) is totally different from grounding a car, which is more of providing a "busbar" of -ve supplies. afaik, the lightning protection does not work this way. in fact, there was an article tat discourage the provision of a grounding belt/ rod fr the car to the tarmac for fear that the current conducted by lightning may enter the car n damage the parts.

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grounding is not compulsory. it act merely to reduce impedance for current resistance.

[Brock]

Hmm...interesting. I know it isn't compulsory. But with it, I'm sure it does make the car electrical systems safer, right? Or am I wrong?

[Apollo]

not any dangerous or safer really.

 

just treat the entire car body as a bus bar distribution for -ve supplies of the battery. the +ve supplies is carried fr the alternator to the battery to the fuse box then to individual appliances. -ve is tap off directly fr the body to form a complete circuit. simplest test is to get a 12V bulb one end stick to +ve on battery and other end touching the car body on any location. except some places but generally u will get a lit bulb.

[Brock]

Apollo,

 

Thanks for the explanation. I think I'm getting a clearer picture now. You electrical grad?

[Apollo]

nope.... unfortunately not.

 

it's just basic direct current. as Shellock would put it "Elementary, Mr Watson"

 

[Brock]

nope.... unfortunately not.

 

it's just basic direct current. as Shellock would put it "Elementary, Mr Watson"

 

U suaning me is it?

[Apollo]

no lah, u got confused by the word grounding.

 

the actual grounding for bldg consist of

a. lightning protection for building which has a copper or aluminum tape spanning the perimeter of the top of the bldg n bonding to anything which is higher. (fact: lightning does not always strike at top of bldg)

this tape down all the way to the ground at various locations and is planted to an electrode bar to disperse the current to the ground.

 

b. grounding / earthing (-ve) involve laying a -ve cable to just abt anything tat is ferrous where occupants may come in contact, eg water pipes and bring this to the Electrical Distribution board, where the excess current r disperse to the lightning protection circuit.

 

this typically handles accidental discharge n excessive current surge.

 

its rather confusing, in simple term, it is for safety but involve alternate current (AC) since the supplies r more lethal in nature, compared to DC which at best will cause skin burn only.

[Maded]

i think your friend's installer messed up... either didn't fuse, or connectors loose...

[Kotila]

Does anyone out there knows the different between parallel and serial grounding, in terms of benefits?

[Apollo]

the right way is actually to loop 1 cable from the alternator body to the nearest part of the car (driver side) and for the rest to flow back to the battery. 1 other cable should b reserved for linking the battery to the base of the ecu.

 

try not to loop betw points, just imagine it like expressways.

[Gadgeter]

Brock,

 

If your friend is really really not convinced... ask him down to MCF meetup...

 

Hmmm... Jazz owner.... Saaber's Jazz is well grounded.

Edited May 12, 2005 by Gadgeter

[Kotila]

I still don't quite understand the difference. What I see is that for the parallel, it required more wire and the serial need less.

[Apollo]

actually not difficult at all. imagine, there is a cable fr the alternator to tbe battery, this is looped fr battery to the car body, so it is like single lane dead end road. to make the road complete (as a loop), u add a cable fr the alternator to the car body farthest fr the battery) and it will come in full circle with one of the grounding points, which connects to the battery.

 

in direct current, impedance plays an impot part. the bulb furthest fr the battery is usually dimmer than the rest. but if u loop the cable back in series, all bulbs shall the similar impedance and they glow in same brightness.

 

cos when u add a cable back fr the last bulb, the current resistance is 1/2. less resistance = better performance.

 

hth