Hi there, the company I work for is considering fitting a 3.5 ton ball hitch to our 26 ton drainage tanker so we can carry extra equipment in a trailer when required.
Apart from getting a company to fit the hitch and electrics, is there anything else required I. E plating etc the driver has a class c+e so is OK to tow
We have done this on various sized rigids of ours. You need to check that the Gross Train Weight on the truck plate does allow enough for whatever trailer you are going to tow, I am sure it will, it is normally only some 7.5t wagons that don’t have this. The ball itself needs to be a heavy duty one, there is a method for calculating the D value but I think when you put the numbers in for a 26t truck in you will find that you cannot buy one with that D number. We just use the strongest available.
Been through DVSA roadside inspections a few times, no questions.
Multi voltage LEDs on the trailer are best then you can use it with a small vehicle easily too. We have a long vehicle board on ours because the combination requires it.
Strangely enough, I believe, the rules that apply to cars etc. regarding towbar certification do not apply to HGV’s, anyone can make one and you are only in trouble if it fails 
. See plenty of horseboxes with the ball bolted to the under run bar 
If the truck is on air then you should not have height problems, we have one on springs so have to adjust the ball position between loaded / unloaded.
Keep a close eye on trailer wheels / tyres as when them little wheels go down a pothole they don’t get any sympathy from your 300hp rigid pulling it, damage is quite common, especially if your trailer is going to be narrower than the truck as the instinct is to avoid the pothole with the truck wheels.
Hope that helps.
Oh and a short, narrow trailer behind a long rigid makes you look like a numpty when you have to reverse. Believe me I spend ages going round the services looking for a drive in, drive out spot 
manski:
We have done this on various sized rigids of ours. You need to check that the Gross Train Weight on the truck plate does allow enough for whatever trailer you are going to tow, I am sure it will, it is normally only some 7.5t wagons that don’t have this. The ball itself needs to be a heavy duty one, there is a method for calculating the D value but I think when you put the numbers in for a 26t truck in you will find that you cannot buy one with that D number. We just use the strongest available.
Been through DVSA roadside inspections a few times, no questions.Multi voltage LEDs on the trailer are best then you can use it with a small vehicle easily too. We have a long vehicle board on ours because the combination requires it.
Strangely enough, I believe, the rules that apply to cars etc. regarding towbar certification do not apply to HGV’s, anyone can make one and you are only in trouble if it fails
If the truck is on air then you should not have height problems, we have one on springs so have to adjust the ball position between loaded / unloaded.
Keep a close eye on trailer wheels / tyres as when them little wheels go down a pothole they don’t get any sympathy from your 300hp rigid pulling it, damage is quite common, especially if your trailer is going to be narrower than the truck as the instinct is to avoid the pothole with the truck wheels.
Hope that helps.
Oh and a short, narrow trailer behind a long rigid makes you look like a numpty when you have to reverse. Believe me I spend ages going round the services looking for a drive in, drive out spot
Thank you for a tip top response, much appreciated, thank you