Q: Boat electrics for beginners - where do I start?
MECO Technical Note MTN 0020
Similar Questions
This MTN Serves the following similar questions;
Boat electrics for complete beginners, where do I start?
What do I need to know to just do the basics? making sure my electrical system is safe and tackling a few basic faults - or at least having a go without making it worse before calling in the pros.
Is there a beginners course I can do as a boat owner to enable me to fix my own wiring?
Are there any courses in marine electrics for someone thinking of becoming a boat sparky?
How do I get my marine electrics ticket?
Quick Answer
Short answer - you can learn a lot before you even start any course - the preview of MET 1 covers the basics of electricity for example - this is a must before you start out in the marine electrical side; even if the course is not for you, this bit is free to access.
There is a fair bit to learn - In the marine world we do not just use standard cable sizes for tasks, we size everything based on load, length of run, and how a cable is routed. Also for fault finding - once you understand what electricity is actually trying to do - it's much easier to figure out where faults are most likely lurking.
Many new learners want to dive into you tube, read standards, wiring diagrams, and marine electrical forums and this type of information is actually fairly dangerous if it is put to use without fully understanding the basics of the raw material - electricity.
The MET 1 course is open to absolute beginners, and to encourage anyone to get started - the most important parts, the basics of electricity, are free to access- you can learn how electricity behaves in a circuit prior to enrolling as a preview to the course ahead.
Why it matters
The simple truth is - once you fully understand how electricity behaves in a circuit, and the relationship between voltage, current, and resistance - if you keep this information in mind you can pretty much understand any electrical system.
It may seem like a complex system at first, and yes there are a lot of things to consider, but for basic fault finding it pays dividends to keep the thought process as simple as can be. lf there is an electrical issue it is down to something somewhere either:
1) connecting something it shouldn't (unwanted short)
or
2) not connecting to something it should (unwanted open)
This same philosophy applies to everything from the simplest electrical system to the most complex electronics.
A solid understanding of, and application of these basics is essential.
Technical explanation
Everything from cable sizing to circuit protection revolves around Ohms Law - the relationship between Voltage, current, and resistance. It makes sense that the longer a cable is the more difficult is is for electricity to flow, so the more energy is lost along the way. To combat this, if we use thicker cables - this is effectively the same as providing more parallel paths for the current to take; so the resistance of thicker cable is less than thinner. Less 'resistance' = less power lost to the cables (voltage drop).
Another situation where the most basic electrical knowledge can save the day is the simple poor connection.
Where 2 current carrying components are deliberately touching, to form an electrical connection, voltage can be lost if these connections are dirty or corroded. This may sound fairly obvious but it's still the most common form of electrical fault, and for faultfinding on older boats - it's a valid assumption. With the right training we pinpoint these voltage drops using simple test gear.
All of these and far more fault finding and system design methods all revolve around a solid understanding of the most basic elements of electricity - specifically Ohms Law and Kirchhoff's Law and the good news is - this section is free right here.
Common mistakes
Diving into 'Marine Wiring' before understanding the raw material - electricity and the relationship between voltage, current and resistance.
Assuming it's the devices that are faulty, before testing for voltage at the device.
Checking off load voltages, it's common to see fake voltages that disappear as soon as load is applied. If your testing the power at a device - make sure its on - or use a sizeable test lamp rather than a multimeter; make the cable do some work.
It's easy to get caught up in the complex finer areas of a system before considering the most basic principles.
Any experienced tech will tell you - check the basics first, before diving into complex diagnostics -
If it should be connected check it is,
if it shouldn't check it isn't!
Standards note
ISO, ABYC
All standards revolve around how electricity behaves in a circuit and assume this knowledge is fully understood.
Technician takeaway
If you're staring out keep it simple - most faults are in fact very simple - once you find them.
The process of fault fining can be made simpler with the test tools covered on the course.
such as
DC clamp meter
in addition to a standard multimeter so you can measure voltage and current at the same time.
If you can run to it - a thermal imaging cameral can lead you directly to a fault - jsut power everything up and check out the bus bars for hot spots.
Look for the green powder - as copper corrodes you'll see green powder - on older boats you can check and re crimp all the heavy DC terminals and gain a few millivolts there.
Covered in MECO training
MET 1
Before diving into the marine electrical subject - the MECO MET 1 provides you with a solid understanding of the basics of how electricity behaves -
The MECO MET 1 course is beginner friendly, and the most important part is included in the free previews, you can try these and if the course is not for you, at least you go away with some important knowledge or a good refresher!
this is covered for free on the MECO MET 1 course here.
The MET one is a great place to start you can learn from the most basic principles and then how this applies to the basic marine electrical system.
you can start here for free